We report on a son and daughter of Ashkenazi-Jewish parents with postaxial polydactyly of the hands and feet associated with syndactyly and brachydactyly, mental retardation, cerebellar hypoplasia, pectus excavatum, mesomelic shortness of the upper and lower limbs, and pretibial dimples. Although this appears to be an example of one of the OFD syndromes and has many similarities to OFD type II, III, IV and VI, it does not fit satisfactorily into any of the types previously described. Thus this may be a new OFD syndrome, although we cannot exclude a possibility that most or all autosomal recessive OFD syndromes are the result of pleiotropy of a single mutation in a homozygous state.