Ohdo blepharophimosis syndrome (OBS) is a multiple congenital anomalies-mental retardation syndrome composed of blepharophimosis, ptosis, dental hypoplasia, partial deafness, and mental retardation. Previously reported cases of OBS have been sporadic except for the report by Ohdo et al. [1986, J Med Genet 23:242-244] that described two affected sisters and a first cousin favoring autosomal recessive inheritance. The original report by Ohdo et al. [1986] may reflect nonpenetrance of an autosomal dominantly inherited disorder or genetic heterogeneity of OBS. We report on a child and the mother who have blepharophimosis, ptosis, dental anomalies, mild hearing loss, and mental retardation. Chromosome analysis in both showed a balanced paracentric inversion of the long arm of chromosome 9, which was also present in two phenotypically normal sibs of the mother. This is the first report of vertical transmission of OBS suggestive of autosomal dominant inheritance. X-linked dominant and mitochondrial inheritance are other possible modes of inheritance.