title: Updating the N syndrome: occurrence of lymphoid malignancy and possible association with an increased rate of chromosome breakage.
abstract: Further studies on a family with the N syndrome, a multiple congenital anomaly/mental retardation syndrome first described by Hess et al in 1974, showed increased chromosome breakage in the affected brothers and in their unaffected mother, all 3 of whom died of lymphoid malignancy. It is suggested that the N syndrome is the result of an X-linked recessive mutation that produces a characteristic MCA/MR syndrome and chromosome instability. We postulate that this chromosome instability in the lymphoid cells of hemizygotes and in approximately half of the lymphoid cells of the heterozygote predisposes to a specific form of lymphoid malignancy.
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D000328:Adult; D002869:Chromosome Aberrations; D005260:Female; D005808:Genes, Recessive; D008040:Genetic Linkage; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics; D007945:Leukemia, Lymphoid / Q000235:genetics*; D008297:Male; D010375:Pedigree; D013577:Syndrome; D014960:X Chromosome