MUSCULO-SKELETAL ABNORMALITIES IN TRISOMY 18

Generalized muscle spasticity is a common finding in trisomy 18. This is thought to account for the decreased movements noted by mothers as well as the overlapping of fingers two and five over three and four.

The characteristic dermal ridge patterns in the hands and feet are also thought to be due to restricted fetal movement in-utero (1).

In the third trimester, a trisomy 18 fetus may demonstrate a fine whole body tremor, persistent extension of the legs, and vertical rather than horizontal eye movements (2).

REFERENCES

1. Taylor AI. Autosomal trisomy syndromes:a detailed study of 27 cases of Edwards' syndrome and 27 cases of Patau's syndrome. J Med Genet 1968;5:227-252.
2. Hepper PG, Shahidullah S. Trisomy 18: behavioral and structural abnormalities. An ultrasonographic case study. Ultrasound Obstet Gynecol 1992;2:48-50.