Siblings, one female and one male, were each born approximately 1 month prematurely and showed microcephalus, shortness, and short limbs plus a receding forehead and one peculiarly positioned small toe. Each failed to thrive, and neither made any developmental progress beyond the newborn status. Each exhibited a similar leukemoid reaction, and one died of respiratory infection at 3 months, the other of seizures and central nervous system infection at 5 months. At autopsy, each had a small brain, hydrocephalus, and bony anomaly of the cranium, the one of the posterior fossa and the other of the foramen magnum; in addition, one had absence of the corpus callosum. The long bones were considered atypical of chondrodystrophy. The combination of midly shortened bones of the extremities, moderately anomalous ribs, and slightly flattened vertebrae with microcrania does not resemble any of the previously recognized forms of short limbed dwarfism. We propose determination by a single, rare, autosomal recessive gene. The parents had greatly different ancestry and their apparent heterozygosity for such a gene made their mating particularly unusual.