Arthrogryposis-like signs in trisomy 18.

Two cases of newborn male infants afflicted with trisomy 18 and with signs of arthrogryposis multiplex congenita (AMC) are described. Anomalies occurring in most cases of trisomy 18 such as polyhydramnios, reduced foetal activity, and skeletal muscle hypoplasia decrease articular movements and, thus might cause AMC. Since AMC is rarely associated with trisomy 18, chromosomal aberration is not the only factor involved in these cases.