Multiple congenital anomalies-hypotonia-seizures syndrome type 2

Multiple congenital anomalies-hypotonia-seizures syndrome type 2 (MCAHS2) is a genetic neurodevelopmental disorder characterized by distinctive facial features, low muscle tone (hypotonia) at birth, myoclonic seizures (which cause jerks or twitches of the upper body, arms, or legs), and various other problems involving the central nervous system, heart, and urinary system. Specific symptoms (especially those not involving the nervous system) and severity vary from person to person, but most children develop severe developmental delay and intellectual disability. This condition is caused by mutations in the PIGA gene on the X chromosome and inheritance is X-linked recessive, so it typically affects boys. However, in some cases, MCAHS2 is not inherited from a parent and is the result of a new mutation occurring for the first time in a person with MCAHS2 (a de novo mutation). Treatment depends on the symptoms present and aims to control symptoms and increase quality of life. The long-term outlook and life expectancy varies depending on severity. Some children with MCAHS2 do not survive beyond infancy.