Isolated anencephaly is a severe birth condition in which a baby does not develop large parts of the brain and skull during very early pregnancy. Early signs of isolated anencephaly are usually seen on prenatal ultrasound, and some pregnancies are also flagged by maternal blood screening. Isolated anencephaly begins before birth and is usually recognized during pregnancy or at delivery. Sadly, most affected babies are stillborn or die within hours or days after birth. There is no cure for isolated anencephaly, so care focuses on clear counseling during pregnancy and comfort care and support for the baby and family.
How many people live with Isolated anencephaly?
There are no meaningful estimates of people living with isolated anencephaly worldwide or in the United States because this severe birth condition is almost always fatal before birth or within hours to days after birth. Doctors instead track how often it happens at birth: in the United States, it affects about 1 in 4,600 births, or roughly 800 babies a year (CDC, 2023), while a single authoritative worldwide count for isolated anencephaly is not consistently reported, although more than 300,000 babies are born each year with serious brain-and-spine birth defects overall worldwide (WHO, 2023), and isolated anencephaly is one part of that larger group.
Overview
Isolated anencephalySymptoms
In isolated anencephaly, major parts of the brain and skull do not develop, so signs are usually seen on prenatal ultrasound or at birth. Babies with isolated anencephaly are unconscious, cannot think or respond normally, and survival is very short.
Outlook and prognosis
Isolated anencephaly is a very serious condition that affects brain and skull development before birth. Most babies are stillborn or live only hours to days after delivery. Families often need intensive emotional, birth, and comfort-care support.
Causes and risk factors
Isolated anencephaly usually results from a neural tube not closing early in pregnancy. Risk rises with low folate, certain anti-seizure medicines, poorly controlled diabetes, obesity, and high fever or overheating. Most cases are not inherited, though genes can contribute.
Genetic influences
Genetics can play a role in isolated anencephaly, but it is usually not caused by one single gene change. Many cases likely reflect a mix of small genetic differences and non-genetic factors.
Diagnosis
Isolated anencephaly is usually suspected during pregnancy on ultrasound, which shows severe skull and brain differences. The diagnosis of isolated anencephaly may be supported by blood tests, and genetic tests are sometimes offered to look for an underlying cause.
Treatment and drugs
Isolated anencephaly is managed with pregnancy monitoring, clear counseling, and support in making care decisions. After birth, treatment focuses on comfort care, warmth, feeding support if possible, and emotional support for the family.
Symptoms
Isolated anencephaly is usually found during pregnancy because the baby's head and brain have not formed in the usual way. The early features of isolated anencephaly are often seen on ultrasound rather than felt as symptoms. Babies born with isolated anencephaly have major differences in skull and brain formation, which affects awareness, breathing, and feeding. In the isolated form, these changes are not part of a broader syndrome.
The early features of isolated anencephaly are often first seen on prenatal ultrasound, sometimes in the first trimester. The top of the skull and the usual outline of the brain are not visible as expected.
Much of the skull and scalp above the eyebrows does not form. This leaves the upper part of the head open and gives the head a very different appearance at birth.
Large parts of the brain, especially the areas needed for thinking, awareness, and sensation, are missing or severely underdeveloped. Because of this, normal consciousness and development are not possible.
Some babies may move their arms or legs, startle, or make brief sounds. These are basic reflexes from lower parts of the nervous system, not purposeful interaction.
How people usually first notice Isolated anencephaly?
How isolated anencephaly is first noticed is usually during pregnancy, often at a routine prenatal ultrasound, where doctors can see that much of the baby’s brain and skull has not developed as expected. Another early clue can be a higher-than-expected level of alpha-fetoprotein, a protein measured in the pregnant person’s blood, which may lead to more detailed imaging. In some cases, the first signs of isolated anencephaly are obvious at birth because the top of the skull is missing and the condition is visible right away.
Types of Isolated anencephaly
No distinct types of Isolated anencephaly are widely recognized.
Can I slow down the onset of symptoms?
No. Isolated anencephaly is a very early birth defect that affects how the brain and skull form, so there is no proven way to slow or delay it once it has started; what can help is lowering the chance of it happening by taking folic acid before pregnancy and in the first weeks of pregnancy, and by having conditions like diabetes and any medicines that may affect early development reviewed with a doctor. If you are planning a pregnancy or could become pregnant, early prenatal care and following standard folic acid guidance can reduce risk for some pregnancies, but they cannot fully prevent this condition.
What genetics can tell you about symptoms
For isolated anencephaly, genetics can help explain why the condition happens in some pregnancies, but they do not usually predict a range of symptoms in the usual sense because this condition causes a very severe, early problem in brain and skull development. In most cases, symptom pattern and severity do not vary much: the condition begins before birth and is almost always severe, although scans may show small differences in how much of the skull and brain are affected. Researchers think inherited genetic differences can raise or lower risk, often together with factors such as folate status, rather than strongly determining when symptoms start or how mild or severe the condition will be.
Causes and risk factors
Isolated anencephaly begins very early in pregnancy when the neural tube does not close fully. It is usually linked to genetic susceptibility, including inherited or new gene changes, rather than one single cause. Low folate before conception and in the first weeks of pregnancy is one of the best-known risk factors. Some anti-seizure medicines, poorly controlled diabetes, obesity, and high body temperature from fever or hot tubs in early pregnancy can also raise risk. It is rarely just one factor, and family history or a previous affected pregnancy can increase the chance of isolated anencephaly in a future pregnancy.
What are the most common causes or risk factors?
Isolated anencephaly usually does not have one single cause. The strongest risk factors are not getting enough folic acid before pregnancy and in the first weeks of pregnancy, having had a past pregnancy affected by a similar problem, or having a family history that suggests an increased genetic tendency, although it usually is not passed down in a simple way. Risk is also higher with some seizure medicines, especially valproate, poorly controlled diabetes, obesity, and high body temperature early in pregnancy, such as from a fever, hot tub, or sauna.
Environmental and biological risk factors
Isolated anencephaly develops very early in pregnancy, often before someone knows they are pregnant. The main risk factors for isolated anencephaly involve body-based factors and outside exposures during this short window. Doctors often group risks into internal (biological) and external (environmental).
Too little folate in the weeks just before and after conception is one of the clearest risk factors for isolated anencephaly. This vitamin is needed when the neural tube is closing very early in development. Problems that reduce folate absorption or use can add to the risk.
Some antiseizure medicines, especially valproate, and some medicines that interfere with folate can raise risk. The concern is greatest if exposure happens in the first month of pregnancy, often before pregnancy is recognized.
Diabetes present before pregnancy can increase the chance of isolated anencephaly, especially when blood sugar is high very early on. High glucose levels can disrupt early development during the brief period when the neural tube is forming.
A fever or repeated exposure to high heat, such as hot tubs or saunas, in very early pregnancy may raise risk. This timing matters because the tissue involved is most sensitive in the first few weeks.
Genetic risk factors
For many families, the hardest question after isolated anencephaly is why it happened and whether it could happen again. Most isolated anencephaly is not caused by one single gene; it usually reflects a mix of inherited factors that affect very early development. Carrying a genetic change doesn’t guarantee the condition will appear. Family history and a previous affected pregnancy are the strongest clues that inherited risk may be playing a role.
Multifactorial pattern: Most isolated anencephaly appears to come from several small inherited factors working together, rather than one clear-cut gene change. This means the genetic causes and risk factors for isolated anencephaly can be present even when no one in the family has had it before.
Family history: Having a close relative who had anencephaly or another neural tube defect raises the chance in a future pregnancy. The closer the relative and the more relatives affected, the stronger this inherited signal tends to be.
Prior pregnancy: If someone has had a past pregnancy affected by anencephaly or a related neural tube defect, the chance is higher in another pregnancy than in the general population. This is one of the clearest clues that shared inherited factors may be involved.
Rare gene changes: In a small number of families, rare changes in genes that guide very early brain and skull development may play a part. When isolated anencephaly happens more than once in a family, genetics specialists may look more closely for this kind of cause.
Lifestyle risk factors
When people ask about lifestyle risk factors for isolated anencephaly, the key issue is maternal health before conception and during the first weeks of pregnancy. Lifestyle habits do not cause the condition after it has already formed, but they can influence the chance that a pregnancy will be affected. The strongest evidence focuses on folate intake, weight and metabolic health, and avoidance of exposures that interfere with early neural tube development.
Too little folate before conception and in very early pregnancy raises the risk of neural tube defects, including isolated anencephaly. Taking folic acid daily and eating folate-rich foods can lower that risk, especially because the neural tube closes before many people know they are pregnant.
Diets low in leafy greens, beans, citrus, and fortified grains can make it harder to maintain adequate folate and other nutrients needed in early fetal development. A more nutrient-dense preconception diet may support lower risk than a pattern dominated by highly processed foods.
Maternal obesity is linked to a higher chance of a pregnancy affected by neural tube defects, including isolated anencephaly. Reaching a healthier weight before pregnancy through eating habits and regular activity may help reduce that risk.
Low physical activity can contribute to obesity and poorer metabolic health, which are both relevant to how lifestyle affects isolated anencephaly risk before pregnancy. Regular exercise is most useful as part of weight management and better glucose control rather than as a direct protective factor on its own.
Risk prevention
For isolated anencephaly, prevention starts before pregnancy because the brain and skull begin forming very early, often before someone knows they are pregnant. The most effective step is getting enough folic acid in the months before conception and in early pregnancy. Prevention is about lowering risk, not eliminating it completely. Some pregnancies are affected despite doing everything recommended, so the goal is to reduce the chance as much as possible.
Taking folic acid every day before pregnancy and during early pregnancy is the best-known way to lower the risk of isolated anencephaly. For most people, this means 400 micrograms daily, while those with a prior neural tube defect-affected pregnancy may need a higher dose prescribed by a doctor.
Because anencephaly develops very early, it helps to start prevention before trying to conceive or if pregnancy is possible. This is one of the main ways to reduce the risk of anencephaly in pregnancy, especially when vitamins are started ahead of time.
Some medicines can raise the risk of neural tube defects, including anencephaly, if taken around conception or in early pregnancy. Talk with your doctor before stopping or changing any prescription, so safer options can be considered if needed.
Poorly controlled diabetes before pregnancy can increase the risk of major birth defects, including isolated anencephaly. Good blood sugar control before conception and in early pregnancy can help lower that risk.
Can you prevent Isolated anencephaly?
You cannot fully prevent isolated anencephaly, and it can happen even when someone does everything right. The best-proven way to lower the risk is to get enough folic acid, a B vitamin, before pregnancy and during the first weeks of pregnancy; it also helps to manage diabetes well and review seizure medicines with a doctor before trying to conceive.
Transmission
Isolated anencephaly is not an infection, so it cannot be caught from someone else or passed through touch, coughing, sex, food, or blood. When people ask how isolated anencephaly is inherited, the key point is that most cases are not passed from parent to child in a simple, predictable pattern.
Instead, isolated anencephaly usually happens from a mix of genetic factors and early pregnancy influences, and many families have no history of it at all. Having had one pregnancy affected by isolated anencephaly can raise the chance in a future pregnancy, but this reflects complex genetic transmission of isolated anencephaly rather than something contagious or highly infectious.
When to test your genes
For isolated anencephaly, routine gene testing usually is not the main tool for early detection; prenatal ultrasound and maternal blood screening are. Genetic counseling, and sometimes targeted testing, can help if you have had a previous affected pregnancy, a strong family history, or features suggesting a broader genetic syndrome.
Diagnosis
Isolated anencephaly is usually diagnosed during pregnancy, often when routine screening shows that the top of the skull and much of the brain did not develop. Getting a diagnosis is often a turning point toward answers and support. In many pregnancies, the diagnosis of isolated anencephaly can be made with ultrasound alone, while other tests may help confirm the finding or look for additional differences.
Ultrasound is the main test used to diagnose isolated anencephaly, often as early as the first trimester and more clearly on the mid-pregnancy anatomy scan. Doctors look for the absence of the skull above the eye level and the exposed or missing upper brain structures.
A maternal blood test may show a very high level of alpha-fetoprotein, also called AFP, which can happen when the fetal neural tube is open. This result does not confirm the condition by itself, but it can support the ultrasound findings and prompt a closer scan.
Your provider may suggest a high-resolution ultrasound to confirm the diagnosis and check whether the anencephaly appears isolated or is happening with other birth differences. In selected cases, fetal MRI may be used when the ultrasound view is limited or more detail is needed.
Genetic tests are not needed to recognize anencephaly itself, but they may be offered if ultrasound shows other unusual findings or if there is a concern about a chromosome condition. This can help clarify whether the finding is truly isolated and can inform future pregnancy counseling.
How is Isolated anencephaly diagnosed?
Isolated anencephaly is usually diagnosed during pregnancy with an ultrasound, which can show that much of the baby’s brain and skull did not develop. A blood test in the pregnant parent may also show a higher-than-usual level of a protein linked with open birth differences, which supports the finding. Genetic testing is not usually needed to make the diagnosis, but doctors may suggest it if there are other unusual findings or questions about the cause.
Stages of Isolated anencephaly
Isolated anencephaly does not have defined progression stages. That is because it is a structural difference in early fetal development rather than a condition that gradually moves from mild to severe over time. In most cases, diagnosis of anencephaly during pregnancy is made with prenatal ultrasound, which can show that major parts of the brain and skull did not develop. Doctors may also use blood tests during pregnancy and, sometimes, fetal MRI to confirm the findings and help families understand what to expect.
Outlook and prognosis
The outlook for isolated anencephaly is unfortunately extremely poor, because the condition is uniformly lethal. Many affected pregnancies end in miscarriage or stillbirth, and among babies born alive, most die within hours to days after birth because the brain and skull have not developed sufficiently to support long-term survival. There is no curative treatment, so care is focused on comfort and support for the infant and family. Maternal health is usually not directly threatened by the fetal condition itself, but the emotional impact on parents can be profound and bereavement support is important. In future pregnancies, the recurrence risk is higher than in the general population but can be reduced substantially by taking folic acid before conception and in early pregnancy.
Long-term effects
For families facing isolated anencephaly, the outlook is sadly very limited. Because key parts of the brain and skull do not develop, isolated anencephaly is not compatible with long-term survival. The long-term picture is often that pregnancy may continue, but babies with isolated anencephaly are usually stillborn or live only a short time after birth.
Isolated anencephaly does not lead to long-term health effects because it is not a condition people survive for months or years. In most cases, babies are stillborn or die shortly after birth, so life expectancy in isolated anencephaly is extremely short.
If a baby is born alive, they may breathe for a brief time but cannot support the basic brain functions needed for ongoing survival. Feeding, awareness, and purposeful responses do not develop in the usual way.
Many pregnancies continue into the second or third trimester, although some end earlier. During pregnancy, doctors may also watch for extra amniotic fluid, which can sometimes cause discomfort or raise the chance of preterm labor.
Isolated anencephaly does not cause long-term effects in the child because survival is very limited, but it can matter for future family planning. After one affected pregnancy, the chance of another neural tube defect is higher than average, though many later pregnancies are unaffected.
How is it to live with Isolated anencephaly?
Isolated anencephaly is not a condition people can live with long term, because the brain and skull do not develop enough to support survival; many affected pregnancies end in miscarriage or stillbirth, and babies who are born alive usually live only hours to days. For parents and loved ones, the daily reality is most often shaped by pregnancy decisions, birth planning, memory-making, and grief, rather than long-term caregiving. This can deeply affect the whole family, and many find that clear medical guidance, perinatal palliative care, and emotional support make an overwhelming time a little more bearable.
Treatment and drugs
Isolated anencephaly cannot be cured, and there is no treatment that can replace the parts of the brain and skull that did not develop during pregnancy. After the diagnosis, care usually focuses on helping the pregnant person understand their options, monitoring their health, and planning for delivery in a way that matches their wishes and medical needs. Supportive care can make a real difference in how you feel day to day, and for a baby born with isolated anencephaly, treatment is centered on comfort care such as warmth, gentle handling, and sometimes medicines to ease discomfort or breathing distress rather than trying to prolong life. Families are often offered perinatal palliative care, bereavement support, and counseling, because treatment for isolated anencephaly also means caring for emotional well-being, not only physical health.
Can you cure Isolated anencephaly?
No, isolated anencephaly cannot be cured. In this condition, large parts of the brain and skull do not develop during pregnancy, and there is no treatment that can replace those missing parts. Care focuses on support during pregnancy, planning for birth, and comfort care for the baby, along with emotional support for the family.
Non-drug treatment
With isolated anencephaly, there is no non-drug treatment that can repair the brain and skull changes, so care centers on comfort, planning, and support for the family. For many, treatment begins not at the pharmacy, but with clear counseling about what to expect during pregnancy, delivery, and the time around the baby's birth. A care team may help with birth planning, newborn comfort care, emotional support, and guidance for future pregnancies.
Ongoing talks with maternal-fetal medicine, neonatology, or genetics teams can help families understand isolated anencephaly and make informed choices. This often includes discussing what may happen during pregnancy, delivery, and shortly after birth.
A written birth plan can spell out wishes for labor, delivery, time with the baby, and comfort-focused care. This can be especially helpful when families are coping with the diagnosis and the early symptoms of isolated anencephaly seen on prenatal scans.
After birth, care is usually focused on keeping the baby warm, clean, and comfortable rather than using invasive treatment. Skin-to-skin contact, gentle handling, and time with family are often central parts of this care.
Perinatal palliative care teams help families prepare for medical decisions, memory-making, and emotional support before and after birth. They can also coordinate care across obstetrics, neonatal teams, and hospice when needed.
Your genes may have an impact on how drugs work for you
For isolated anencephaly, there is no medicine that can treat or reverse the condition, so inherited differences in how drugs work are not usually a main part of care. Some genetic differences can affect how the body handles folate, the B vitamin in folic acid, which matters more for prevention before and very early in pregnancy than for treatment after the condition is found. If there is a family history or another pregnancy is being planned, a genetics or prenatal care specialist can help review folic acid needs and any medicines that may raise the chance of this kind of birth difference.
Pharmacological treatments
With isolated anencephaly, there is no medicine that can repair the missing parts of the brain and skull after this condition has developed. Sometimes medicines are taken short-term for pregnancy care, delivery, pain control, or recovery, rather than to treat isolated anencephaly itself. Folic acid is important because it can help prevent some future pregnancies from being affected, but it does not treat an existing case.
There is no drug treatment that can reverse isolated anencephaly or change the baby’s brain development after diagnosis. In practice, treatment for isolated anencephaly during pregnancy focuses on comfort, delivery planning, and support for the pregnant person and family.
Folic acid, also called vitamin B9, is used before conception and in early pregnancy to lower the chance of neural tube defects in a future pregnancy. It is a preventive vitamin, not a treatment for a pregnancy already affected by isolated anencephaly.
If labor is induced, doctors may use misoprostol or oxytocin to help the uterus contract and start or strengthen labor. These medicines are used to manage the delivery process safely, not to treat the condition itself.
Pain medicines during labor or after delivery may include acetaminophen, ibuprofen, or epidural medicines such as bupivacaine, sometimes combined with fentanyl. The choice depends on the stage of care, overall health, and personal preferences.
Genetic influences
When a pregnancy is affected by isolated anencephaly, many families want to know why it happened and whether it could happen again. It’s natural to ask whether family history plays a role. For isolated anencephaly, genetics can matter, but the pattern is usually complex rather than caused by one single inherited gene. Researchers think small differences in several genes involved in early brain and spinal cord development, and in how the body uses folate, may raise risk, often together with other factors such as low folate levels, certain medicines, diabetes, or obesity. Most pregnancies affected by isolated anencephaly happen in families with no known history, but the risk of isolated anencephaly in a future pregnancy is somewhat higher after one affected pregnancy. If there have been repeated neural tube defects, other birth differences, or close relatives with similar problems, genetic counseling may help clarify whether testing is worth considering, although testing often does not find one clear genetic cause.
Is Isolated anencephaly genetic?
Genetics can play a role in isolated anencephaly, but it is usually not caused by one single gene change. Many cases likely reflect a mix of small genetic differences and non-genetic factors.
Having a genetic risk is not necessarily a diagnosis
Genetic variants are a normal part of being human and are common across the general population. Most do not have a direct effect on health and simply reflect natural human diversity. For many genes, having a variant linked with a condition suggests a possible connection rather than a certain diagnosis, especially when several genes and environmental factors are involved. In some situations, though, one well-understood variant in a particular gene can be enough to confirm the diagnosis.
Pharmacogenetics—how genetics influence drug effects
For families facing isolated anencephaly, the difficult reality is that there is no medicine or surgery that can repair the missing parts of the brain and skull once this has developed. Because of that, genetics usually do not change drug treatment for the baby; care is focused on confirming the diagnosis, supporting the pregnancy, planning delivery, and offering comfort care if the baby is born alive. Not every difference in response is genetic, but in isolated anencephaly, genetic testing is used more to look for an underlying chromosome or gene condition and to estimate the chance of it happening again than to choose a medication. Some gene changes involved in how the body handles folate may raise risk, so the most practical treatment-related step is often prevention in a future pregnancy with folic acid started before conception. After one pregnancy affected by isolated anencephaly or another neural tube defect, many doctors recommend a higher folic acid dose, often 4 mg daily, although the exact plan should be individualized. In short, genetics can help guide counseling and prevention, but they rarely change the immediate treatment options for isolated anencephaly.
Interactions with other conditions
In isolated anencephaly, the main medical issues are present from very early pregnancy rather than caused by another illness acting on it later. Because it is called isolated, it usually happens on its own and is not part of a broader syndrome with a predictable pattern of other diseases. Another important aspect is how it may link with other diseases: doctors may look carefully for other major birth differences, but many cases of isolated anencephaly do not come with a separate underlying disorder. In pregnancy, some health conditions in the pregnant parent, such as diabetes, can raise the chance of neural tube defects, but they do not “interact” with isolated anencephaly in the way two ongoing diseases might affect each other. If families are asking whether isolated anencephaly is tied to later medical conditions in the baby, the answer is generally no, because this condition is severe from birth and is usually considered a single developmental defect rather than part of a disease combination.
How genes can cause diseases
Humans have more than 20,000 genes, each carrying out one or a few specific functions in the body. One gene instructs the body to digest lactose from milk, another tells the body how to build strong bones and another prevents the body's cells from beginning to multiply uncontrollably and developing into cancer. As all of these genes combined are the building instructions for our body, a defect in one of these genes can have severe health consequences.
Through decades of genetic research, we know the genetic code of any healthy/functional human gene. We have also identified that in certain positions on a gene, some individuals may have a different genetic letter from the one you have. We call these hotspots "Genetic Variations" or "Variants" in short. In many cases, studies have been able to show that having the genetic letter "G" in the position makes you healthy, but having the letter "A" in the same position disrupts the gene function and causes a disease. Genopedia allows you to view these variants in genes and summarizes all that we know from scientific research, which genetic letters (Genotype) have good or bad consequences on your health or on your traits.
What other conditions can cause similar symptoms to Isolated anencephaly?
The conditions most often confused with isolated anencephaly are other severe birth differences that affect how the skull and brain form, especially acrania, where the skull bones are missing, and encephalocele, where brain tissue pushes out through an opening in the skull. Early in pregnancy, doctors may also consider the closely related acrania-exencephaly-anencephaly sequence, because these changes can look very similar on an ultrasound. Less often, other major brain and skull differences can raise similar concerns until imaging shows the exact problem.
History
For many families, isolated anencephaly enters the story very early in pregnancy, often during a scan that shows the baby’s skull and brain have not developed in the usual way. Although the diagnosis can feel very modern because it is often found with ultrasound, the condition has been recognized for a very long time in medical writing and in descriptions of pregnancy loss and birth differences.
Across cultures and time periods, people described babies born with severe differences involving the head, even though they did not understand the cause. Early accounts were limited to what could be seen at birth, and older terms were often broad or imprecise. As medical science evolved, doctors began to separate isolated anencephaly from other conditions that can affect the brain, skull, or spine, which helped make diagnosis more accurate and improved the way cases were recorded.
In the 20th century, better pathology, prenatal imaging, and public health tracking changed how isolated anencephaly was understood. Researchers learned that it belongs to a group of early developmental conditions called neural tube defects, which happen very early in pregnancy, often before someone knows they are pregnant. That history matters today because it explains why early symptoms of isolated anencephaly are usually not symptoms felt by the pregnant person, but findings seen on prenatal testing.
Another major step came when studies showed that folic acid can lower the chance of some neural tube defects. This led to changes in pregnancy advice and, in some countries, food fortification programs. Researchers later identified a genetic contribution in some families, but the history of isolated anencephaly also made clear that this is not caused by anything a parent did or did not do in day-to-day life.
Today, isolated anencephaly is understood far better than it was in the past, both medically and emotionally. Diagnosis is usually made before birth, and care now includes clearer counseling, support for decision-making, and attention to the needs of grieving families. Knowing this history helps explain why prevention, early prenatal care, and compassionate support are such central parts of care now.