Patau syndrome
Summary
Patau syndrome is a rare, severe genetic disorder caused by trisomy 13, resulting in multiple congenital anomalies and profound intellectual disability. Most affected infants die within the first year of life due to severe cardiac and CNS defects.
Detail
Patau syndrome results from nondisjunction during meiosis leading to an extra copy of chromosome 13 (trisomy 13). The incidence is approximately 1 in 16,000 live births, with maternal age being a risk factor. Classic features include severe intellectual disability, microcephaly, holoprosencephaly (incomplete separation of cerebral hemispheres), cleft lip/palate, polydactyly, and rocker-bottom feet. Cardiac defects are common, including ventricular septal defects, patent ductus arteriosus, and hypoplastic left heart syndrome. Ocular abnormalities include microphthalmia, colobomas, and cataracts. Renal anomalies such as cystic dysplastic kidneys frequently occur. Omphalocele and neural tube defects may also be present. Diagnosis is confirmed by karyotype analysis showing 47,XY,+13 or 47,XX,+13. Prenatal diagnosis is possible through amniocentesis or chorionic villus sampling. The prognosis is extremely poor, with 50% mortality by 1 month and 90% by 1 year. Management is primarily supportive care, with consideration of comfort measures due to the severe nature of the condition.
Sources
- Nelson Textbook of Pediatrics
- Thompson & Thompson Genetics in Medicine
- Emery and Rimoin's Principles and Practice of Medical Genetics
- First Aid for the USMLE Step 1
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