Patterned macular dystrophy 1 is a rare inherited eye condition that affects the macula, the part of the retina needed for sharp central vision. Many living with Patterned macular dystrophy 1 have few or no early changes, but some notice blurred or distorted central vision, trouble reading, or difficulty seeing fine detail over time. It may help to know that doctors have studied this condition for decades, and not everyone will have the same experience. The condition is often recognized in adulthood, tends to be lifelong, and severe vision loss is uncommon, though vision can worsen in some people. Treatment usually focuses on regular eye follow-up, low-vision support when needed, and checking for complications, especially if early symptoms of Patterned macular dystrophy 1 begin to affect daily tasks.
How many people live with Patterned macular dystrophy 1?
Global and U.S. estimates for patterned macular dystrophy 1 are not consistently reported by major rare disease references such as Orphanet and OMIM, and it is often grouped with other rare inherited eye conditions instead of being counted on its own. Because of that, the number of people living with patterned macular dystrophy 1 worldwide or in the United States is currently unknown.
Overview
Patterned macular dystrophy 1Symptoms
Patterned macular dystrophy 1 often causes mild central vision changes, such as blurry spots, trouble reading, or needing brighter light. Many people keep good side vision. Eye doctors may see distinctive pigment patterns in the macula.
Outlook and prognosis
Patterned macular dystrophy 1 often changes slowly, and many keep useful central vision for years, especially early on. Some may notice reading, faces, or dim-light tasks become harder over time, while side vision usually stays good.
Causes and risk factors
Patterned macular dystrophy 1 usually results from an inherited gene change, often passed in an autosomal dominant pattern, though some cases arise new. Age, smoking, and overall eye health may influence when symptoms start and how severe they become.
Genetic influences
Genetics are central to Patterned macular dystrophy 1, which is usually caused by inherited changes in the PRPH2 gene. These genetic variations help explain why it runs in families and why symptoms can differ even among relatives.
Diagnosis
Diagnosis of Patterned macular dystrophy 1 usually starts with an eye exam and retinal imaging that shows a characteristic pattern. Doctors may confirm Patterned macular dystrophy 1 with genetic tests, along with clinical features and family history.
Treatment and drugs
Treatment for Patterned macular dystrophy 1 usually focuses on regular eye checks and monitoring changes in central vision. If abnormal blood vessels or swelling develop, eye injections such as anti-VEGF medicines may help. Magnifiers and brighter lighting can also make reading easier.
Symptoms
Patterned macular dystrophy 1 often affects sharp, central vision, so tasks like reading small print, recognizing faces, or seeing fine detail may take more effort. Many people with patterned macular dystrophy 1 notice little or no change at first, while others develop mild blurring or distortion in the center of vision. Features vary from person to person and can change over time. Because this is an inherited eye condition, some of the earliest clues may show up on an eye exam before they cause clear day-to-day problems.
Vision in the middle of what you see may look slightly blurry or less sharp. This can make reading, sewing, or other close-up tasks harder even when side vision stays fairly good.
Straight lines may start to look bent, rippled, or uneven. People often notice this when looking at door frames, text on a page, or tiles in a kitchen or bathroom.
Words can seem faded, crowded, or harder to keep in focus. What once felt effortless can start to require more energy or focus, especially with small print.
Seeing facial features, labels, or other small details may become more difficult. Many living with patterned macular dystrophy 1 find that brighter light or magnification helps.
How people usually first notice Patterned macular dystrophy 1?
Patterned macular dystrophy 1 is often first noticed not at birth, but later when subtle changes in central vision begin to matter, such as blurred reading vision, mild distortion, or colors seeming a little less crisp. For many people, the first signs of patterned macular dystrophy 1 are easy to miss, and the condition may first come to light during a routine eye exam when an eye doctor sees distinctive pigment changes in the macula, the part of the retina responsible for sharp, detailed sight. Because symptoms can be mild at first and may vary even within the same family, how patterned macular dystrophy 1 is first noticed can differ from person to person.
Types of Patterned macular dystrophy 1
No distinct types of Patterned macular dystrophy 1 are widely recognized.
Can I slow down the onset of symptoms?
At this time, there is no good evidence that lifestyle changes or medicines can meaningfully delay the start of symptoms in patterned macular dystrophy 1, an inherited eye condition that affects the macula, the part of the eye used for sharp central vision. Healthy habits such as not smoking and managing blood pressure and blood sugar are good for overall eye health, but they have not been proven to prevent this condition or stop it from starting; regular eye exams can still help by catching changes or rare complications early. Research is ongoing, so it is reasonable to focus on general eye health and follow-up care, while being honest that this cannot guarantee a later onset.
What genetics can tell you about symptoms
In patterned macular dystrophy 1, genetics can help explain why symptoms vary so much, even within the same family: some people have only mild blurred or distorted central vision for many years, while others develop more noticeable reading or detail-vision problems earlier. Changes linked to this condition are known to affect when symptoms begin and how severe they become, but they do not let doctors predict the exact course for any one person. In short, genetic testing can support the diagnosis and give clues about expected variation, but it usually cannot say with certainty which symptoms someone will have or how quickly they will change.
Causes and risk factors
If reading starts to feel harder or straight lines look bent, Patterned macular dystrophy 1 is usually caused by an inherited gene change that affects the macula. The biggest risk factor is a family history of Patterned macular dystrophy 1, because this gene change is often passed from parent to child. Having a gene change doesn’t mean you’ll definitely develop the condition. Age and overall eye health can shape when symptoms begin and how much vision changes over time. Smoking may put extra stress on the retina, but lifestyle factors are not thought to be the main cause.
What are the most common causes or risk factors?
Patterned macular dystrophy 1 is most often caused by an inherited change in a gene, usually the PRPH2 gene, that affects the macula, the small part of the retina that helps you see fine detail. The main risk factor is family history, because it often runs in families and can be passed down from just one affected parent. There are no well-proven lifestyle or environmental causes, although signs of the condition often do not appear until adulthood.
Environmental and biological risk factors
When people look into risk factors for patterned macular dystrophy 1, the main finding is that few outside or body-based triggers have been proven. Doctors often group risks into internal (biological) and external (environmental). For this condition, current evidence does not show clear links with pregnancy exposures, birth complications, or common environmental factors. In other words, most commonly discussed outside risks are unconfirmed.
Researchers have not confirmed pollution, radiation, infections, or chemical exposures as causes of patterned macular dystrophy 1. At this time, these are not established environmental risk factors.
Conditions during pregnancy, such as diabetes, high blood pressure, or infections, have not been clearly shown to increase the chance of patterned macular dystrophy 1. No specific maternal biological risk factor is widely accepted.
Prematurity, low birth weight, and delivery complications are not known to make patterned macular dystrophy 1 more likely. Current evidence does not support these as proven biological risk factors.
Advanced maternal or paternal age has not been established as a risk factor for patterned macular dystrophy 1. This differs from some congenital conditions where older parental age can play a role.
Genetic risk factors
In patterned macular dystrophy 1, the main risk comes from inherited changes that affect the light-sensitive center of the retina. The genetic causes of patterned macular dystrophy 1 most often involve PRPH2, a gene that helps retinal cells keep their shape and function. Carrying a genetic change doesn’t guarantee the condition will appear, because signs can be mild, delayed, or vary widely even within one family. For many living with patterned macular dystrophy 1, the clearest clue is a family history of similar central vision changes.
PRPH2 variants: The best-established genetic cause of patterned macular dystrophy 1 is a harmful change in the PRPH2 gene. This gene supports important parts of retinal cells, so a variant can gradually affect the macula and central vision.
Autosomal dominant: Patterned macular dystrophy 1 is usually inherited in an autosomal dominant pattern, meaning one changed copy of the gene can be enough to raise risk. If a parent carries the variant, each child has a 1 in 2, or 50%, chance of inheriting it.
Family history: Having a parent, brother, sister, or child with patterned macular dystrophy 1 makes an inherited cause more likely. Sometimes relatives were labeled with a different macular condition because this disorder can look a little different from one family member to another.
Variable expression: The same genetic variant can affect relatives in different ways. Some may develop clearer retinal changes earlier, while others have mild findings or are not diagnosed until a routine eye exam later in life.
Lifestyle risk factors
Patterned macular dystrophy 1 is an inherited retinal condition, so lifestyle habits do not cause it. Still, how lifestyle affects Patterned macular dystrophy 1 can matter for visual comfort, retinal stress, and the chance of added eye damage over time. The most relevant lifestyle risk factors for Patterned macular dystrophy 1 are habits that can worsen macular strain or increase the burden of other eye disease.
Smoking does not cause Patterned macular dystrophy 1, but it can increase oxidative stress in the retina and may add to macular damage over time. It also raises the risk of other eye problems that can further reduce central vision.
Long-term exposure to intense sunlight or bright glare may increase light-related stress on the macula. Wearing UV-blocking sunglasses and reducing harsh glare can help limit extra retinal strain.
A diet low in vegetables, fruit, and omega-3-rich foods may reduce support for overall retinal health. Good nutrition will not reverse the genetic change, but it may help the eye cope better with ongoing stress.
Obesity, poor blood sugar control, and unhealthy eating patterns can harm blood vessels and may worsen the eye's ability to tolerate disease-related stress. Managing these factors may lower the chance of additional retinal or vascular problems affecting vision.
Risk prevention
Patterned macular dystrophy 1 is usually inherited, so there is no proven way to prevent the condition itself from developing. For many living with Patterned macular dystrophy 1, prevention is mainly about protecting vision, lowering strain on the eyes, and catching changes early. Prevention is flexible—it adapts to your life and health background.
Regular visits with an eye specialist can help track subtle vision changes before they interfere more with reading, driving, or screen use. This is especially helpful because early symptoms of Patterned macular dystrophy 1 can be mild and easy to miss.
Wearing sunglasses that block UV light may help reduce extra stress on the retina when you are outdoors. A brimmed hat can add another layer of protection in bright sun.
Smoking can harm blood flow and increase oxidative stress in the back of the eye. If you have Patterned macular dystrophy 1, not smoking may help support overall retinal health.
Keeping blood pressure, cholesterol, and blood sugar in a healthy range supports the small blood vessels that nourish the retina. Alongside medical care, everyday habits also matter.
Can you prevent Patterned macular dystrophy 1?
No, patterned macular dystrophy 1 usually cannot be prevented because it is an inherited eye condition caused by a gene change passed through families. Healthy habits can support overall eye health, but they are not known to stop this condition from developing. If it runs in your family, genetic counseling may help you understand the chance of passing it on, but it cannot guarantee prevention.
Transmission
Patterned macular dystrophy 1 is not infectious, so it cannot spread from one person to another through touching, kissing, coughing, sex, blood, or sharing food or rooms. Instead, the genetic transmission of Patterned macular dystrophy 1 usually happens within families.
In many living with Patterned macular dystrophy 1, the condition is inherited in an autosomal dominant pattern, which means one changed copy of the gene from either parent can be enough to pass it on. In practical terms, each child of an affected parent has a 1 in 2, or 50%, chance of inheriting it, although some cases can start with a new genetic change and no earlier family history.
When to test your genes
Consider genetic testing if you or close relatives have patterned changes in the macula, central vision changes, or a family history of inherited retinal disease. Testing can help confirm the diagnosis, clarify inheritance, guide family counseling, and support monitoring with an eye specialist.
Diagnosis
Many living with Patterned macular dystrophy 1 first learn something is wrong after a routine eye exam or when reading, seeing fine detail, or adjusting to dim light becomes harder. Diagnosis is usually based on the pattern of changes at the back of the eye and then confirmed with specialized eye tests, and sometimes genetic testing. Getting a diagnosis is often a turning point toward answers and support.
An eye specialist asks about blurred or distorted central vision, trouble with fine detail, and when changes began. A detailed family and health history can help because Patterned macular dystrophy 1 may run in families.
The doctor widens the pupils with eye drops to look closely at the macula, the part of the retina used for sharp central vision. In Patterned macular dystrophy 1, they may see pigment changes with a distinctive patterned appearance.
Photos and scans of the retina help show the exact location and shape of the macular changes. These imaging findings are often central to the diagnosis of Patterned macular dystrophy 1 and help track whether the condition is stable or changing over time.
Optical coherence tomography, often called OCT, uses light waves to create detailed cross-section images of the retina. It can show buildup of material under the retina or changes in the retinal layers that support the diagnosis.
How is Patterned macular dystrophy 1 diagnosed?
Patterned macular dystrophy 1 is usually diagnosed by an eye specialist after asking about vision changes and family history, then examining the back of the eye with the pupils widened using drops. The doctor often uses special photos and scans of the retina, especially the center used for sharp vision, to look for the typical patterned changes and to rule out other causes of blurry or distorted central vision. A genetic test may sometimes be used to support the diagnosis or help clarify it in families with several affected members, but the diagnosis is mainly based on the eye exam and retinal imaging.
Stages of Patterned macular dystrophy 1
Patterned macular dystrophy 1 does not have defined progression stages. This is because it usually does not follow a clear step-by-step pattern over time, and vision changes can be mild, slow, and different from one person to another. Early symptoms of Patterned macular dystrophy 1 may include blurred central vision, trouble reading, or noticing that straight lines look slightly distorted, while some people have few symptoms at first. Doctors usually start with a conversation about vision changes, then use an eye exam and retinal imaging to look for the typical pattern in the macula and monitor whether it is staying stable or changing.
Outlook and prognosis
The outlook for patterned macular dystrophy 1 is often relatively favorable, because many affected people retain useful central vision for years and the disease usually progresses slowly. Visual symptoms can remain mild into midlife, although some individuals develop increasing blur, distortion, difficulty reading, or problems with detailed central tasks over time. Prognosis is variable even within families, and a minority of patients may experience more noticeable vision loss if macular atrophy, choroidal neovascularization, or other retinal complications develop. Regular follow-up with an ophthalmologist is important so that treatable complications are recognized early and low-vision support can be offered if needed. Life expectancy is not generally affected, and patterned macular dystrophy 1 is not usually associated with increased mortality.
Long-term effects
For many living with patterned macular dystrophy 1, the long-term picture is often one of slow change rather than sudden vision loss. Vision can stay fairly good for years, but central sight may become less sharp or more distorted over time, especially in adulthood. Long-term effects vary widely, and some people have only mild changes while others develop more noticeable trouble with detailed visual tasks. Peripheral, or side, vision is often less affected than the center of vision.
The main long-term effect is gradual change in central vision, which can make straight lines look wavy or make fine detail harder to see. Many people with patterned macular dystrophy 1 notice this most when reading, recognizing faces, or doing close work.
Over time, daily routines may take longer because small print, labels, phone text, and other detailed tasks can become harder to manage. Early symptoms of patterned macular dystrophy 1 are often subtle, so these changes may build slowly rather than all at once.
Some people remain stable for long periods, while others have a slow decline in sharp central sight over many years. Even within the same family, patterned macular dystrophy 1 can affect long-term vision differently.
In some cases, the light-sensitive center of the retina develops areas of thinning or damage that lead to a more permanent drop in central vision. Less commonly, abnormal blood vessels can grow under the macula and cause faster worsening.
How is it to live with Patterned macular dystrophy 1?
Living with patterned macular dystrophy 1 often means dealing with gradual changes in central vision, the part you use for reading, recognizing faces, driving, and seeing fine detail, while side vision usually stays much better. Many people with this condition can keep up with most daily routines for years, but some may find they need brighter light, magnifiers, larger print, or more time for close-up tasks as vision changes. Because it can be hard for others to see that central vision is affected, family, friends, and coworkers may need to understand why certain tasks become tiring or why extra visual support matters.
Treatment and drugs
Patterned macular dystrophy 1 is usually managed with regular eye exams rather than a cure, because many people keep useful vision for years and may only notice mild changes at first, such as trouble reading small print or needing brighter light. Treatment often looks different for each person, since some living with patterned macular dystrophy 1 need only monitoring, while others may benefit from updated glasses, brighter task lighting, magnifiers, or other low-vision tools to make daily activities easier. If the condition leads to complications such as abnormal blood vessels or swelling in the center of the retina, eye doctors may treat these with medicines injected into the eye to help protect vision. Because the early symptoms of patterned macular dystrophy 1 can be subtle and the course can vary, follow-up care with an eye specialist is an important part of treatment.
Can you cure Patterned macular dystrophy 1?
No, there is no cure right now for patterned macular dystrophy 1. Care usually focuses on regular eye checkups, watching for changes in central vision, and using tools like updated glasses, brighter lighting, or magnifiers to make reading and other close-up tasks easier. If a complication develops, an eye specialist may be able to treat it to help protect vision.
Non-drug treatment
Day-to-day, patterned macular dystrophy 1 can make reading, recognizing faces, or seeing in dim light more tiring, even when side vision stays fairly good. There is no proven non-drug treatment that reverses the retinal changes, so care usually focuses on protecting useful vision and making daily tasks easier. For many, treatment begins not at the pharmacy, but with practical tools, vision training, and regular follow-up to catch changes early. Some people also ask about the early symptoms of patterned macular dystrophy 1 when planning work, driving, or family life.
Low vision specialists can help you make the most of the sight you still have. This may include training in reading strategies, contrast use, and ways to scan more effectively when central vision is patchy.
Handheld magnifiers, stand magnifiers, large-print devices, and electronic video magnifiers can make reading labels, bills, or phone screens easier. You may need to try more than one strategy before finding what works best for your home, job, and hobbies.
Brighter, well-placed lighting often helps with close work and reduces eye strain. Simple routines—like using task lamps or boosting contrast at home—can have lasting benefits.
Many living with patterned macular dystrophy 1 find glare bothersome, especially outdoors or under harsh indoor lights. Tinted lenses, sunglasses, or anti-glare filters can improve comfort and sometimes make details easier to pick out.
Your genes may have an impact on how drugs work for you
For people with patterned macular dystrophy 1, there is not yet clear proof that the inherited changes linked to the condition reliably change how most routine eye treatments work. In day-to-day care, genetic testing is usually more helpful for confirming the diagnosis and understanding family risk than for choosing a medicine, because treatment often focuses on watching the retina closely and treating problems if they appear. If a related problem such as leaking or abnormal blood vessel growth develops, your eye doctor may choose treatment based on what they see in the eye rather than on a genetic result.
Pharmacological treatments
Most people with patterned macular dystrophy 1 do not need a routine medicine just for the retinal pattern itself, especially if vision is stable. Drug treatment is usually considered only if a complication develops, most importantly abnormal new blood vessels or fluid leakage under the macula. In that setting, the main treatment for patterned macular dystrophy 1 is often a medicine injected into the eye by a retina specialist. Not everyone responds to the same medication in the same way.
There is no standard pill or eye drop that reverses patterned macular dystrophy 1 itself. For many living with this condition, treatment means regular eye checks so changes can be caught early.
Medicines such as ranibizumab, aflibercept, and bevacizumab may be used if fragile leaking blood vessels grow under the macula. This is the most common drug-based treatment for patterned macular dystrophy 1 when vision suddenly worsens or scans show swelling.
Verteporfin may be used with a light-based treatment in selected cases, though it is used less often now than anti-VEGF medicines. Your retina specialist may consider it if the leaking area has a pattern that makes this approach more suitable.
Genetic influences
If patterned macular dystrophy 1 shows up in several relatives, that fits with what doctors know about this condition: it is usually inherited in an autosomal dominant pattern. That means one altered copy of the relevant DNA region can be enough to cause the condition, and each child of an affected parent has a 50% chance of inheriting it. In many families, the change is found in a stretch of DNA near the PRDM13 gene, which helps guide early development of the macula, the part of the retina needed for sharp central vision. Even within the same family, the genetic change can affect people differently, so some may have mild findings on an eye exam while others notice more central vision changes. To put these pieces together, doctors may suggest genetic counseling and sometimes genetic testing for patterned macular dystrophy 1, especially when relatives want clearer information about family risk.
Is Patterned macular dystrophy 1 genetic?
Genetics are central to Patterned macular dystrophy 1, which is usually caused by inherited changes in the PRPH2 gene. These genetic variations help explain why it runs in families and why symptoms can differ even among relatives.
Having a genetic risk is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are found throughout the general population. Most of these variants do not directly affect health and simply reflect natural differences among people. In many genes, having a variant associated with a condition points to a possible link, not a certain diagnosis, particularly when several genes and environmental influences play a role. In other situations, though, one well-understood variant in a particular gene may by itself be enough to confirm a diagnosis.
Pharmacogenetics—how genetics influence drug effects
For many living with Patterned macular dystrophy 1, treatment is usually less about a specific pill and more about regular visits with an eye specialist, watching for changes in central vision, and treating complications if they appear. Variants in certain genes may help explain why the condition runs in families, but at this point they usually do not point to a specific drug or dose for Patterned macular dystrophy 1. In other words, there is no well-established pharmacogenetic test that routinely tells doctors which medicine will work best for Patterned macular dystrophy 1. Genetic testing can still be useful because it may confirm the diagnosis, help clarify the chance that relatives could also be affected, and sometimes help people join research studies or future gene-based treatment programs. If problems such as leaking blood vessels or fluid in the macula develop, treatment may include eye injections or other retina care similar to what is used for related eye diseases, and the choice is usually based on what the eye exam and scans show rather than on the gene result. For many, this means genetics matters most for understanding the condition and planning care, while day-to-day treatment is guided mainly by symptoms, eye findings, and follow-up imaging.
Interactions with other conditions
For many people living with patterned macular dystrophy 1, the biggest day-to-day issue is central vision changes, so other eye conditions can make reading, driving, or recognizing faces more difficult. It is not usually known for causing a long list of related illnesses throughout the body, but doctors may pay close attention if someone also has common eye problems such as cataracts, glaucoma, or diabetic eye disease, because these can add to vision loss. Another important aspect is how it may link with other diseases. Patterned macular dystrophy 1 can also resemble age-related macular degeneration on an eye exam, especially when early symptoms of patterned macular dystrophy 1 are mild, so getting the diagnosis right matters. In some families, patterned macular dystrophy 1 appears alongside other inherited retinal conditions, but the pattern can vary from person to person. If vision seems to worsen faster than expected, an eye specialist may look for another eye disease happening at the same time rather than assuming patterned macular dystrophy 1 is the only cause.
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 Patterned macular dystrophy 1?
Other problems that affect the macula, the small center part of the retina that gives you sharp straight-ahead vision, can look a lot like patterned macular dystrophy 1. The main ones doctors often think about are age-related macular degeneration, Stargardt disease, and Best disease or a similar inherited macula problem called adult-onset vitelliform dystrophy, and sometimes a fluid leak under the retina called central serous retinopathy. These can all cause blurred or distorted central vision and trouble reading, so an eye specialist often uses imaging tests to tell them apart.
History
Long before eye scans could show the retina in fine detail, doctors were already noticing that some families developed a similar pattern of slow, central vision changes over time. People living with patterned macular dystrophy 1 may not realize at first that the condition has a long medical history, because early changes can be subtle and often look like other common eye problems.
Initially understood only through symptoms, later reports focused on the distinctive markings seen at the back of the eye. As retinal photography and specialist eye exams improved during the 20th century, doctors began separating this condition from other forms of macular disease. That mattered because patterned macular dystrophy 1 often follows a different course from age-related macular degeneration, even though both can affect reading, recognizing faces, or seeing fine detail straight ahead.
Over time, descriptions became more precise as specialists learned that these pigment changes could appear in several recognizable shapes and patterns. Not every early description was complete, yet together they helped build the modern view of the condition as a group of related retinal disorders with similar features. For many, this has meant fewer misunderstandings and a better chance of getting the right diagnosis when early symptoms of patterned macular dystrophy 1 are first investigated.
In more recent decades, imaging tests such as optical coherence tomography and specialized retinal pictures have made it easier to spot the condition earlier and follow how it changes. Researchers later identified a genetic cause for this type of retinal disease, which helped confirm that it is not simply a wear-and-tear problem of aging. Even so, the history of patterned macular dystrophy 1 is still one of careful observation: what began as puzzling changes seen during eye exams gradually became a clearer, better recognized diagnosis.