title: Bloom syndrome in a Mexican mestizo girl.
abstract: A 3-year-old girl with Bloom syndrome is described. She exhibited stunted growth of prenatal onset and defective immunity, but the typical skin manifestations were absent. Cytogenetic analysis revealed a 46,XX complement, 12.2% of metaphases with at least a structural aberration, and a ten-fold increase in the sister-chromatid exchange rate. Leukocyte beta-glucuronidase activity was reduced to about 1/3; the significance of this finding is not clear. The present observation demonstrates the variable expression of the disorder probably depending on ethnic and constitutional factors.
mesh_terms: D001816:Bloom Syndrome / Q000235:genetics*; D002675:Child, Preschool; D002869:Chromosome Aberrations; D005260:Female; D006801:Humans; D007621:Karyotyping; D008800:Mexico; D012854:Sister Chromatid Exchange