We report on a patient with agenesis of corpus callosum, mental retardation, and unusual hitherto undescribed bone changes. The latter include multiple Wormian bones, thin ribs, short, straight, laterally tapering clavicles, small iliac bodies, high iliac angles, triangular areas of sclerosis in the iliac bones, minimal metaphyseal irregularity, striated trabecular pattern in some metaphyses, granular ossification pattern of the patellae, hypoplastic distal phalanges, minimal flatness of phalangeal epiphyses, and retarded bone age. This patient represents a new mental retardation syndrome with agenesis of corpus callosum and unusual bone changes.