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Combined immunodeficiency, chromosomal instability, and postnatal growth deficiency in a Japanese girl
M Yamada1, S Matsuura, M Tsukahara
1Department of Pediatrics, Hokkaido University School of Medicine, Sapporo, Japan. masayama@gred.hokudai.ac.jp
Insights
This study details a rare case of combined immunodeficiency and chromosomal instability in an 11-year-old girl. Her unique presentation suggests a potentially new genetic disorder, distinct from known syndromes.
Area of Science:
- Immunology
- Genetics
- Cell Biology
Background:
- Combined immunodeficiency (CID) and chromosomal instability are severe genetic disorders.
- Ataxia-telangiectasia (A-T) and Nijmegen breakage syndrome (NBS) are known conditions presenting with these features.
Observation:
- An 11-year-old Japanese girl presented with growth deficiency, microcephaly, polydactyly, and recurrent infections.
- Immunological evaluation revealed lymphocytopenia and reduced immunoglobulin levels.
- Fibroblast analysis showed spontaneous chromosome aberrations and hypersensitivity to radiation.
Findings:
- The patient exhibited combined immunodeficiency, chromosomal instability, and radiation hypersensitivity.
- Clinical and laboratory data excluded ataxia-telangiectasia and Nijmegen breakage syndrome.
- Mutational analysis of the NBS1 gene was negative, ruling out NBS.
Implications:
- The patient's condition represents a novel combination of immunodeficiency and chromosomal instability.
- This case may indicate a new genetic disorder requiring further investigation.
- Understanding this new disorder can advance knowledge of DNA repair and immune function.
Abstract:
We report on an 11-year-old Japanese girl with combined immunodeficiency and chromosomal instability. She had postnatal growth deficiency and microcephaly, preaxial polydactyly of the left hand, and susceptibility to infections. Immunological studies showed marked lymphocytopenia (around 500/ll), reduced lymphocyte response to various mitogens, and reduced or absent serum IgA, IgG, and IgM. Cell biological studies of her primary skin fibroblasts demonstrated spontaneous chromosome aberrations and radiation hypersensitivity. The combination of immunodeficiency, chromosomal instability, and radiation hypersensitivity as seen in the girl is present in both ataxia-telangiectasia and Nijmegen breakage syndrome. Ataxia-telangiectasia was excluded because of differences in clinical features and laboratory data. Likewise, Nijmegen breakage syndrome is unlikely to be the case because the characteristic face, hyperpigmented spots, and mental retardation present in the syndrome were missing in the girl. Sequence analysis of a Nijmegen breakage syndrome responsible gene, NBS1, revealed no mutations. A normal NBS1 product was also demonstrated by immunoblot analysis using an anti-NBS1 antibody. We propose that the disorder in the girl represents a new combination of combined immunodeficiency and chromosomal instability.