The case of an 11-year-old girl with a severe bleeding diathesis, a factor IX level of 4 per cent, and 45, X Turner’s syndrome is described. Family studies revealed severe factor IX deficiency in 4 male relatives and mild deficiencies in 4 heterozygous female carriers. The Bm or B+ variant of this disorder was demonstrated in all affected members of the kindred.

1. Two morphologically distinct populations of erythrocytes were found in a mother and in two of her daughters, one of whom (the proband) was anemic. One erythrocyte population was morphologically normal; the other was hypochromic and microcytic. 2. The X-linked blood group antigen, Xga, was present in erythrocytes from the mother and the two daughters, but not in erythrocytes from the father. The daughters were, therefore, heterozygous for the gene controlling this antigen. 3. Separation of the two populations of erythrocytes was accomplished by centrifugation in layered gum acacia solutions of different specific gravity. 4. The microcytic cells from the three affected individuals were Xga-positive. Isolated normal cells were Xga-positive in the mother, but negative in both daughters. These data suggest that the erythrocyte defect is X-linked and that the phenomenon of X-inactivation applies to genes controlling both the morphologic defect and the Xga antigen. 5. The free protoporphyrin content of the isolated microcytes was lower than that of the normal cells. The capacity of the microcytes to convert delta-aminolevulinic acid to protoporphyrin was unimpaired. On these bases it is suggested that the hereditary defect lies either at or before the step in which delta-aminolevulinic acid is synthesized.

Of 15 patients with Turner's syndrome studied for renal anomalies by intravenous pyelogram, 11 had demonstrable abnormalities ; three had horseshoe kidney. None had evidence of impaired renal func tion. Four reported previous urinary tract infections. Similarities among the positional and structural abnormalities of the kidneys suggested a continuum of morphologic changes, with a possible re lationship of such changes to impaired positional information pro gramming by the developing abnormal gonad during embryogenesis.

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