Prenatal diagnosis of Rambam-Hasharon syndrome

Rambam-Hasharon syndrome (RHS) is a newly recognized autosomal recessive inborn error in fucose metabolism. Mental retardation, short stature, coarse facies, and recurrent infections are the main clinical findings. Several fucosilated proteoglycans are deficient in these patients. Leukocyte adhesion deficiency type 2 is associated with lack of the membrane glycoprotein sialyl-Lewisx (CD15s). In the red blood cells (RBCs), lack of the membrane glycoprotein H is manifested as a Bombay (Oh) blood type. Two consecutive pregnancies it risk for RHS were monitored during mid-trimester by cordocentesis. One fetus expressed H substance 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 type. The placenta of the affected fetus was small and irregular. This is the first prenatal diagnosis of this syndrome and the first case found in a female. The documentation of the syndrome in patients of both sexes and the parental consanguinity support an autosomal recessive inheritance. 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 causing multiple deficiencies of fucosilated proteoglycans.