NACC1-related neurodevelopmental disorder with epilepsy, cataracts and episodic irritability is a rare condition that affects brain development. This disorder is caused by changes in one copy of the NACC1 gene and can lead to a range of challenges involving development and neurological function. People with this condition may experience developmental delays and intellectual disabilities, in addition to episodes of extreme irritability. Some may also have seizures (epilepsy), eye problems like cataracts, and difficulties with feeding. Other features can include low muscle tone (hypotonia), delayed myelination in the brain, a smaller than average head size (microcephaly), and stereotypic hand movements. Gastrointestinal issues and sleeping problems have also been observed in some cases.

The disorder is marked by several common symptoms. These include developmental delay, intellectual disability, and epilepsy, along with cataracts and feeding difficulties. In addition, people with this condition can have episodes of extreme irritability. Other symptoms noted include hypotonia, delayed myelination, microcephaly, stereotypic hand movements, gastrointestinal issues, and sleeping problems.

This condition is caused by heterozygous variants in the NACC1 gene. These genetic changes affect the normal development and function of the brain, leading to the symptoms observed in this disorder.