Symmetrical terminal transverse limb defects: report of a twenty-week fetus.

A 20-week gestation hydropic Thai fetus is reported who had symmetrical absence of each hand and forefoot with persistence of digit-like nubbins on each limb. The histologic studies showed there was calcified acellular material in the digit-like nubbins, consistent with infarcted blood vessels, and cartilaginous structures that represented possibly the distal metacarpal articulating surface. The red blood cell indices of both parents were consistent with their being heterozygous for a hemoglobinopathy, such as alpha-thalassemia, which is common in Thais. The infarcted blood vessels could be the result of thrombosis of the digital arteries in the fetus due to a hemoglobinopathy such as hemoglobin Bart's, just as rabbit fetuses homozygous for brachydactyly have transverse terminal digit amputations following digital vessel occlusions due to macrocytic anemia. This was the only child with symmetrical absence of the hands and feet identified among 123,489 liveborn and stillborn infants surveyed for major malformations.