R368X mutation in MID1 among recurrent mutations in patients with X-linked Opitz G/BBB syndrome

Opitz G/BBB syndrome is a genetically heterogeneous condition, with both autosomal dominant and X-linked forms. The MID1 gene is associated with X-linked Opitz G/BBB syndrome. Most mutations identified are unique, which makes it difficult to assess possible genotype/phenotype correlations. We report on a familial c.1102C>T (p.R368X) mutation in the MID1 gene, previously reported by Cox et al. (Hum Mol Genet 9:2553-2562, 2000), and document it as a recurrent mutation causing Opitz G/BBB syndrome. This mutation may result in various midline defects, including cleft lip/palate, laryngeal cleft, hypertelorism, Dandy-Walker malformation, ventricular septal defect and hypospadias in male patients, with intrafamilial variability. Seven other mutations (c.712G>T, c.829C>T, c.1108A>G, c.1444_1447dupAACA, c.1483C>T, c.1798dupC and entire gene deletions) have been previously reported as recurrent mutations. The presented family with the c.1102C>T mutation provides additional information about the clinical consequences of the nonsense mutation causing premature truncation of the protein at the level of the COS domain. (C) 2014 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.