(1988) and Erickson (1999) commented on the high frequency of SCID among Athabascan Indians. No skeletal abnormalities were detected on radiographic examination, and 3 patients tested had normal adenosine deaminase ( 608958) and purine nucleoside phosphorylase ( 164050) activity (see also POPULATION GENETICS below). All had lymphopenia and hypogammaglobulinemia, and most had absent tonsils and lymph nodes. All patients presented within the first months of life with oral thrush, diarrhea, fever, pneumonia, and/or failure to thrive. (1980) reported 5 infants with T-, B- SCID from the Navajo and Jicarilla Apache Indians of the U.S. (1993) found that cells from 3 patients with autosomal recessive T-, B- SCID had increased radiosensitivity of granulocyte macrophage colony-forming units (GM-CFU) similar to scid mice, whereas cells from controls and a patient with the X-linked SCID phenotype ( 300400) showed normal radiosensitivity. (1998) excluded involvement of the RAG1, RAG2, PRKDC ( 600899), XRCC4 ( 194363), DNA ligase I (LIG1 126391), and DNA ligase IV (LIG4 601837) genes, all of which are involved in the process of V(D)J recombination or DNA repair.Ĭavazzana-Calvo et al. Susceptibility to radiation also implicated a defect in the DNA repair machinery. There was a lack of coding joint formation however, normal signal joint formation suggested that the final ligation step of the broken DNA ends was not affected. Functional expression studies in cells derived from these patients showed a defect in the DNA repair machinery necessary for the completion of recombination of the variable (V), diversity (D), joining (J) segments that generate variable types of immunoglobulins and T-cell receptors required for proper immune function. (1998) reported 3 sibs, born of consanguineous parents, and 1 unrelated patient with T-, B- SCID whose cells showed increased sensitivity to ionizing radiation. (1991) found that a subset of cells from T-, B- SCID patients showed increased radiosensitivity. Severe combined immunodeficiency, X-linked Severe combined immunodeficiency due to ADA deficiency SCID, autosomal recessive, T-negative/B-positive typeīare lymphocyte syndrome, type II, complementation group B Severe combined immunodeficiency, B cell-negativeīare lymphocyte syndrome, type II, complementation group Dīare lymphocyte syndrome, type II, complementation group A Severe combined immunodeficiency, Athabascan type Severe combined immunodeficiency with microcephaly, growth retardation, and sensitivity to ionizing radiation Bare lymphocyte syndrome, type II, complementation group Eīare lymphocyte syndrome, type II, complementation group C
0 Comments
Leave a Reply. |