Keys to Diagnosis and Management of Smith-Lemli-Opitz Syndrome

After Down Syndrome and Fragile X Syndrome, a new syndrome that causes congenital mental retardation has been described by Smith, Lemli, and Opitz, in 1964 as a syndrome with genital ambiguity, sexual dysgenesis, and mental retardation. The incidence of Smith-Lemli-Opitz Syndrome (SLOS) is 1:20,000 and 1:40,000 among Caucasians. SLOS, the third leading cause of congenital mental retardation, is a genetic syndrome with autosomal recessive transmission and intrauterine onset. The aim of this book chapter is to present the SLOS, with all its genetic, metabolic, malformative, and biochemical aspects, as well as the probability of recognition and diagnosis.