PRENATAL-DIAGNOSIS OF RAMBAN-HASHARON SYNDROME

Rambam-Hasharon syndrome (RHS) is a newly recognized autosomal recessi ve inborn error in fucose metabolism. Mental retardation, short statur e, coarse facies, and recurrent infections are the main clinical findi ngs. Several fucosilated proteoglycans are deficient in these patients . Leukocyte adhesion deficiency type 2 is associated with lack of the membrane glycoprotein sialyl-Lewis(x) (CD15s). In the red blood cells (RBCs), lack of the membrane glycoprotein H is manifested as a Bombay (Oh) blood type. Two consecutive pregnancies at risk for RHS were moni tored during mid-trimester by cordocentesis. One fetus expressed H sub stance and her blood phenotype was O Rh+. The second fetus, a female, was 2 weeks smaller than expected by dates and had the Bombay blood ty pe. The placenta of the affected fetus was small and irregular. This i s the first prenatal diagnosis of this syndrome and the first case fou nd in a female. The documentation of the syndrome in patients of both sexes and the parental consanguinity support an autosomal recessive in heritance. Two apparent recombinations between fucosyl-transferase 1 ( FUT1, the H gene) and fucosyl-transferase 2 (secretor) are suggestive of non-allelic heterogeneity. We believe that the Bombay phenotype in this family is caused by a mutated gene, other than FUT1, which is cau sing multiple deficiencies of fucosilated proteoglycans.