Miller-Dieker syndrome is a condition characterized by a pattern of abnormal brain development called lissencephaly. Normally, the surface of the brain (cerebral cortex) has folds and grooves. Lissencephaly causes the surface of the brain to be abnormally smooth, with fewer folds and grooves. In people with Miller-Dieker syndrome, lissencephaly is typically associated with severe intellectual disabilities, developmental delays, weak muscle tone (hypotonia), and seizures. Seizures usually begin in the first few months of life.

In the majority of cases, Miller-Dieker syndrome is caused by a deletion of genetic material near the end of the short (p) arm of chromosome 17. This area of chromosome 17 is called the MDS critical region. Though the size of the deleted segment varies among affected individuals, it typically includes the PAFAH1B1 and YWHAE genes.

Miller-Dieker syndrome appears to be a rare disorder, although its exact prevalence is unknown.

In most cases, Miller-Dieker syndrome is not inherited. The chromosome 17 deletion is usually a random event that occurs during the formation of reproductive cells (eggs or sperm) or during early fetal development. Affected people typically have no history of the disorder in their family.

Published Date: November 14, 2024
Published By: National Institutes of Health