Anatomical defects in a case of trisomy 13 with a D/D translocation.

Gross morphological defects and variations in a cytogenetically confirmed case of trisomy 13 with t (D/D) are described comprehensively for the first time. The subject, a female neonate, exhibited the following clinical features: microcephaly, sloping forehead, coloboma of the iris, bilateral cleft lip and palate, short neck, and postaxial extra digits on hands and feet. Visceral anomalies included: dextrocardia; hypertrophied right ventricle; common atrium; hypertrophied sinus venosus; persistent left superior vena cava; a large, patent ductus arteriosus interventricular septal defect; Meckel diverticulum; common mesentary; omphalocele; accessory renal arteries and veins; bicornuate uterus; bilateral agenesis of the olfactory bulb; partial holoprosencephaly; and the ulnar nerve passed anterior to the medial epicondyle, bilaterally. Supernumerary muscles included: pectorodorsalis ("achselbogen"); chondroepitrochlearis; sternochondroscapularis; accessory heads of biceps brachii; and radiocarpus. The following muscles were absent: stylohyoideus; pectoralis minor (left); subclavius; palmaris longus and brevis; plantaris; and peroneus tertius. The following muscles exhibited unusual variations: digastricus; mylohyoideus; pectoralis major; and extensor indicis. These findings are compared and contrasted with those recently reported in primary trisomy 13 and 18 and with a case of trisomy 13 with a D/G translocation.