Autosomal-recessive microcephaly in two siblings, one with normal IQ and both with protruding mandible, small ears, and curved nose.

We report on 2 sibs with severe microcephaly and unusual associated manifestations. The brother has borderline/normal intelligence, episodic seizures, clumsiness, and the more severe of facial manifestations; the sister has normal IQ and neither seizures nor behavior abnormalities. Small ears, markedly protruding midface, curved nose, and severe retrognathia are present in both sibs. We postulate that our patients have a "new" form of AR microcephaly, since normal intelligence is not found, nor are the associate findings as pronounced, as in other, more common forms of AR microcephaly (i.e., "microcephalia vera").