Two CpG mutational hot spots in the X-linked interleukin-2 receptor gamma chain gene (IL2RG) may cause 15% of all human severe combined immunodeficiency

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:134275

Pepper, A E; Puck, J M ^[1]; Liu, X ^[2]

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1. National Center for Human Genome Research, Bethseda, MD (United States)
2. Univ. of Pennsylvania School of Medicine, Philadelphia, PA (United States)

Severe combined immunodeficiency (SCID), a syndrome of profoundly impaired cellular and humoral immune function, is caused by various autosomal gene defects, including adenosine deaminase (ADA) deficiency, as well as mutations in the X-linked IL2RG gene encoding the gamma chain of the lymphocyte receptor for IL-2. Mutational analysis of IL2RG was performed using genomic DNA from males with SCID referred from genetics and immunology centers. Single strand conformation polymorphisms (SSCP) were sought by PCR amplification of each of the 8 IL2RG exons using labelled flanking primers. Sequence of exons with aberrant SSCP detected a majority of unique deleterious IL2RG mutations in 30 unrelated SCID patients. However, multiple mutations were seen at CpG dinucleotides, known to be C{yields}T transversion sites. cDNA 690-691 in exon 5 was mutated in 4 patients, 1 patient with each of the C{sub 690}{yields}T causing an Arg{yields}Cys substitution, and 1 with G{sub 691}{yields}A causing Arg{yields}His. Two other patients had SCID caused by a single mutation in IL2RG exon 7. This C{sub 879}{yields}T, also in a CpG, changed an Arg to STOP, resulting in loss of the SH2-related intracellular domain. In addition to our patients, 1 patient with each of the C{sub 690} and the C{sub 879} mutations have been reported by others, giving an overall incidence of 20% from our lab and 21% from all reported IL2RG SCID mutations. While ADA defects account for approximately 15% of SCID, a striking male SCID predominance suggest up to 70% of the cases are X-linked, due to IL2RG mutation. Thus, screening for mutations at the 2 CpG hot spots we have found in IL2RG can identify the genotype of as many SCID cases as are found by ADA testing.

• OSTI ID: 134275
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
AMINO ACIDS
DETECTION
DNA SEQUENCING
EXONS
GENE MUTATIONS
GENES
GENOTYPE
HEREDITARY DISEASES
HUMAN X CHROMOSOME
IMMUNE SYSTEM DISEASES
LYMPHOCYTES
MALES
NUCLEOTIDES
POLYMERASE CHAIN REACTION
RECEPTORS