Simpson-Golabi-Behmel Syndrome, Type 2

A number sign (#) is used with this entry because of evidence that Simpson-Golabi-Behmel syndrome type 2 (SGBS2) is caused by mutation in the OFD1 gene (300170) on chromosome Xp22. One such family has been reported.

See also orofaciodigital syndrome type I (OFD1; 311200), an allelic disorder with a different phenotype.

Clinical Features

Budny et al. (2006) reported a Polish family in which 9 males had developmental delay, macrocephaly, and respiratory problems inherited in an X-linked recessive pattern. All affected males except the proband died at an early age. The proband was an 11-year-old boy with severe mental retardation, dysmorphic facies, high-arched palate, low-set ears, broad thumbs, short fingers, and obesity. He had repeated respiratory infections, and functional studies of respiratory cilia showed a disorganized ciliary beating pattern with lack of coordination.

Inheritance

The transmission pattern of SGBS2 in the family reported by Budny et al. (2006) was consistent with X-linked recessive inheritance.

Molecular Genetics

In 2 affected members and all female obligate carriers of an affected Polish family, Budny et al. (2006) identified a 4-bp duplication in the CXORF5 gene (300170.0007). Female carriers were unaffected.