An MCA/MR syndrome with hypocholesterolemia due to familial hypobetalipoproteinemia: report of a second patient with Nguyen syndrome.

[Nguyen et al. (2003); Am J Med Genet 121A: 109-112] reported a boy with severe hypocholesterolemia due to autosomal dominant hypobetalipoproteinemia (ADBHL) associated with severe growth retardation, mental deficiency, epicanthal folds, a short nose with low nasal bridge and anteverted nares and bilateral partial cutaneous syndactyly of toes 2 and 3. Many of these manifestations resembled those in a mild form of Smith-Lemli-Opitz syndrome (SLOS). We report on a 13-year-old boy with ADHBL, who manifested a SLOS-like phenotype, including mental retardation and a characteristic face, similar to that of a patient reported by [Nguyen et al. (2003); Am J Med Genet 121A: 109-112]. Our patient supports the hypothesis by [Nguyen et al. (2003); Am J Med Genet 121A: 109-112] that ADHBL induced cholesterol deficiency has a significant effect on morphogenesis during embryogenesis, although additional genetic or environmental factors may be required to develop an SLOS-like phenotype in individuals with ADHLB. This is a second case of Nguyen syndrome.