Many families first notice something is different when a baby with 8q24.3 microdeletion syndrome has low muscle tone, feeds slowly, or misses early motor milestones like head control or rolling. Doctors may pick up the first signs of 8q24.3 microdeletion syndrome during a newborn exam or early check-ups because of poor growth, unusual facial features, or developmental delays; sometimes it’s suspected prenatally if an ultrasound shows growth concerns or structural differences. Genetic testing is usually how 8q24.3 microdeletion syndrome is first noticed with certainty after these early clues prompt evaluation.