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. © 2005 Wiley‐Liss, Inc.