Macrocephaly-intellectual disability-autism syndrome

Macrocephaly-intellectual disability-autism syndrome (also known as MIDAS or macrocephaly-autism syndrome) is a rare genetic neurodevelopmental disorder characterized by the combination of macrocephaly (abnormally large head circumference), intellectual disability of variable severity, and autism spectrum disorder. This condition is primarily caused by mutations in the PTEN gene (phosphatase and tensin homolog), which plays a critical role in regulating cell growth and proliferation. The syndrome predominantly affects the central nervous system, leading to cognitive and behavioral challenges, but can also have implications for other organ systems due to the tumor suppressor function of PTEN. Key clinical features include macrocephaly that is often present at birth or develops in early childhood, developmental delay, intellectual disability ranging from mild to severe, and autism spectrum disorder with associated social communication difficulties and repetitive behaviors. Additional features may include seizures, hypotonia (low muscle tone), and motor delays. Some individuals may also exhibit overgrowth features, skin findings such as penile freckling or lipomas, and an increased predisposition to certain benign and malignant tumors (including thyroid, breast, and endometrial cancers) due to the underlying PTEN dysfunction. The phenotypic spectrum can overlap with other PTEN hamartoma tumor syndromes, including Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome. There is currently no cure for macrocephaly-intellectual disability-autism syndrome. Management is supportive and multidisciplinary, involving early intervention programs, speech and language therapy, occupational therapy, behavioral therapy (including applied behavior analysis for autism), and special education services. Given the increased cancer risk associated with PTEN mutations, affected individuals require lifelong cancer surveillance following established PTEN-specific screening guidelines. Seizures, if present, are managed with standard antiepileptic medications. Genetic counseling is recommended for affected families to discuss recurrence risks and implications for relatives.

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