The Ashkenazic Jewish Bloom syndrome mutation blmAsh is present in non-Jewish Americans of Spanish ancestry.

Bloom syndrome (BS) is more frequent in the Ashkenazic Jewish population than in any other. There the predominant mutation, referred to as "blmAsh," is a 6-bp deletion and 7-bp insertion at nucleotide position 2281 in the BLM cDNA. Using a convenient PCR assay, we have identified blmAsh on 58 of 60 chromosomes transmitted by Ashkenazic parents to persons with BS. In contrast, in 91 unrelated non-Ashkenazic persons with BS whom we examined, blmAsh was identified only in 5, these coming from Spanish-speaking Christian families from the southwestern United States, Mexico, or El Salvador. These data, along with haplotype analyses, show that blmAsh was independently established through a founder effect in Ashkenazic Jews and in immigrants to formerly Spanish colonies. This striking observation underscores the complexity of Jewish history and demonstrates the importance of migration and genetic drift in the formation of human populations.

Encephalopathy and fatty metamorphosis of the liver associated with cold-agglutinin autoimmune hemolytic anemia.

Three patients with encephalopathy clinically indistinguishable from Reye syndrome but associated with elevated cold-agglutinin titers and antiglobulin-I autoimmune hemolytic anemia are reported. The patients were treated with exchange transfusions, dexamethasone, controlled hyperventilation, and intracranial pressure monitoring. Liver biopsy specimens in two of the three patients showed fatty infiltration of the hepatocytes, but the light microscopic and electron microscopic appearance of the liver was not typical for Reye syndrome. These patients are reported to alert physicians to a metabolic encephalopathy in children which mimics Reye syndrome, but is distinctly different in clinical course and complicated by cold agglutinins and an autoimmune hemolytic anemia.