Innis and Hedera (2004) reported 2 unrelated boys with isolated left mirror hand and ulnar duplication. One patient had preaxial polydactyly of the left hand and limited flexion and extension of the left elbow and wrist. The left hand had 8 fingers and no thumb. Radiographic analysis showed absence of the radius and ulnar duplication; the left shoulder and upper arm were normal. The second child had a flexed wrist with 7 digits on the left hand and no thumb. Radiographic analysis of the left upper limb showed 2 ulnae and 7 triphalangeal digits. His father had a unilateral clubfoot and his mother had a mild hallux valgus. Neither child had nasal abnormalities. Innis and Hedera (2004) suggested that these patients had 'segmental' Laurin-Sandrow syndrome due to somatic mutation involving the precursor cells of the left upper limb.