title: Heterogeneity in Roberts syndrome.
abstract: Roberts syndrome (RS) is a rare, autosomal recessive condition characterized primarily by growth retardation, developmental delay, and limb anomalies. Some RS patients (RS+), but not others (RS-), have an abnormality of their constitutive heterochromatin (the "RS effect"). RS+ patients also show a cellular hypersensitivity to DNA damaging agents such as mitomycin C (MMC). Lymphoblastoid cell lines from 2 unrelated RS+ patients were fused and hybrid cells examined for correction of the RS effect and MMC hypersensitivity. Neither cellular defect was corrected in the 2 hybrid cell lines examined, suggesting that these 2 patients represent a single complementation group. Fusions were also performed between one RS+ cell line and 2 different RS- cell lines. In both fusions, the hybrids demonstrated correction of both the heterochromatin abnormality and MMC hypersensitivity. These observations suggest that RS+ and RS- patients belong to different complementation groups and do not arise from the same single gene mutation.
authors.affiliation: Department of Genetics, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: D J
authors.initials: DJ
authors.lastname: Allingham-Hawkins
authors.forename: D J
authors.initials: DJ
authors.lastname: Tomkins
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D002460:Cell Line; D002658:Developmental Disabilities / Q000235:genetics; D005260:Female; D018740:Genetic Heterogeneity; D006130:Growth Disorders / Q000235:genetics; D006801:Humans; D006822:Hybrid Cells; D007231:Infant, Newborn; D017880:Limb Deformities, Congenital; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects; D016685:Mitomycin / Q000494:pharmacology; D013577:Syndrome
chemical_list: D016685:Mitomycin