Smith-Lemli-Opitz syndrome/RSH syndrome

Initially described in 1964 this is an inborn error of metabolism of in the steroid synthesis pathway. This syndrome was initially called RSH after the first initial of the last names of the first 3 patients evaluated!

 

This syndrome is caused by a deficiency of the microsomal enzyme DHCR7(Dehydrocholesterol reductase 7), which is responsible for conversion of 7DHC to cholesterol as the last step in cholesterol synthesis. Affected children hence have low plasma cholesterol levels and elevated levels of cholesterol precursors (e.g. 7DHC).

 

Clinical features are variable and include llethargy, rrespiratory failure, deafness, feeding difficulties, failure to thrive, photosensitivity, mental retardation, autism, antisocial, self-destructive, and violent acts , intrauterine growth retardation (IUGR), microcephaly, broad nasal tip with anteverted nostrils, micrognathia, ptosis, squint, congenital cataracts, low-set ears, syndactyly and/or polydactyly, hypospadias or cryptorchidism in males and ambiguous genitalia in females, cleft palate and congenital cardiac defects.