FULL MONOSOMY-21, PRENATALLY DIAGNOSED BY FLUORESCENT IN-SITU HYBRIDIZATION

We describe a case of full monosomy 21 which was prenatally diagnosed in chorionic villi by fluorescent in situ hybridization (FISH). Becaus e of intrauterine fetal death, a curettage was performed and cytogenet ic analysis of skin fibroblasts confirmed the presence of monosomy 21 in fetal cells. DNA investigations showed a paternal origin of the sin gle chromosome 21. Inspection and autopsy of the fetus revealed severa l congenital malformations. Some of them have been reported in earlier studies of monosomy 21; others concern new observations. Regarding th e eye, the following abnormalities were microscopically observed: abse nce of the anterior and posterior eye chambers, aniridy, a hypoplastic ciliary body, Peter's anomaly, and a double retina with secondary dys plasia. In addition, malformations of the extremities were seen: parti al, proximal syndactyly of digits 3 and 4 of the right hand; pes varus position of the right foot; and transverse reduction defect at the ta rsals of the left foot. To our knowledge, this is the first case in wh ich full monosomy 21 has been proven. (C) 1997 by John Wiley & Sons, L td.