Trisomy 8 syndrome. The rib anomaly and some new features in two cases.

Two further cases of trisomy 8 syndrome are reported. Both displayed characteristic anomalies of the ribs. An index of variation in rib diameter was constructed, and the value was found to differ from that in normal children. Our first patient, who was examined post mortem, had an atresia of the gallbladder and common mesentary. Patient 2 had muscular hypotonia and atrophy. She also showed an anomaly of the perineum, where the posterior commissure of the vulva was absent and the mucosae of the vulva and anus met at the midline, a defect which has not been described previously as a part of the syndrome. Otherwise, both present patients had abnormalities already known typical for the syndrome. The literature is reviewed, and the features of the trisomy 8 syndrome are divided into three groups - major, minor and inconstant, to facilitate the diagnosis.