BCOR and Oculofaciocardiodental Syndrome

Abstract

Abstract In 1980, Hayward described a female with canine (cuspid) radiculomegaly associated with congenital cataracts (Hayward, 1980). Further cases of individuals with similar dental anomalies and congenital cataracts were reported by Marashi and Gorlin (1990, 1992). Wilkie et al. (1993) proposed that this phenotype, in combination with distinctive cardiac and facial findings, comprised a novel syndrome and the term oculofaciocardiodental (OFCD) syndrome was recommended to refer to this disorder (Gorlin et al., 1996). Due to recent changes in nomenclature, OFCD syndrome is now referred to as syndromic microphthalmia 2 (MCOPS2; OMIM 300166). However, the term OFCD syndrome is used throughout this chapter. Since it was defined, the condition has been reported around 30 times, exclusively in females. In 2004, Ng et al. demonstrated that presumed null mutations in the X-linked BCL-6 corepressor (BCOR) gene, which encodes BCOR, are responsible for OFCD syndrome (Ng et al., 2004). Since those individuals tested have skewed inactivation in favor of the wild type allele, it is presumed that OFCD syndrome is X-linked dominant with male lethality. In addition to causing OFCD, a missense mutation in BCOR has been described in a single family with MCOPS2 (X-linked recessive Lenz microphthalmia syndrome), suggesting a correlation between mutation type and phenotype.