Cerebellar Vermis Aplasia With Associated Features Suggesting Smith-Lemli-Opitz Syndrome And Meckel Syndrome

Lowry (1983) discussed the overlap of the Smith-Lemli-Opitz syndrome (270400) and the Meckel syndrome (249000). The 2 syndromes had apparently not been seen together in the same sibship until the report by Casamassima et al. (1987). These workers described a new syndrome in 3 members of 1 sibship: in the first 2 children the disorder resembled the Smith-Lemli-Opitz syndrome and in the third it resembled the Meckel syndrome. In addition, all 3 children had cerebellar defects similar to those described in the Joubert syndrome (213300). The affected children were 2 sisters and a brother with nonconsanguineous parents of mixed European ancestry. The patients were the second, fifth, and seventh pregnancies of this couple. The third patient, whose condition resembled Meckel syndrome, had a large occipital meningoencephalocele, postaxial hexadactyly, immature glomeruli and dilated collecting ducts in the kidney, and periportal fibrosis and bile duct accentuation in the liver. The first child died at age 18 months, the second at age 2 days; both showed absence of the cerebellar vermis. Thompson and Baraitser (1987) suggested that the disorder reported by Thompson and Baraitser (1986) and by Hunter et al. (1974) is the same condition and that 'for the time being at least, it should be considered an entity separate from either Smith-Lemli-Opitz or the Meckel syndromes.'