Molecular analysis of mutations in a patient with purine nucleoside phosphorylase deficiency.

Published

Journal Article

Purine nucleoside phosphorylase (PNP) deficiency is an inherited autosomal recessive disorder resulting in severe combined immunodeficiency. The purpose of this study was to determine the molecular defects responsible for PNP deficiency in one such patient. The patient's PNP cDNA was amplified by PCR and sequenced. Point mutations leading to amino acid substitutions were found in both alleles. One point mutation led to a Ser-to-Gly substitution at amino acid 51 and was common to both alleles. In addition, an Asp-to-Gly substitution at amino acid 128 and an Arg-to-Pro substitution at amino acid 234 were found in the maternal and paternal alleles, respectively. In order to prove that these mutations were responsible for the disease state, each of the three mutations was constructed separately by site-directed mutagenesis of the normal PNP cDNA, and each was transiently expressed in COS cells. Lysates from cells transfected with the allele carrying the substitution at amino acid 51 retained both function and immunoreactivity. Lysates from cells transfected with PNP alleles carrying a substitution at either amino acid 128 or amino acid 234 contained immunoreactive material but had no detectable human PNP activity. In summary, molecular analysis of this patient identified point mutations within the PNP gene which are responsible for the enzyme deficiency.

Full Text

Duke Authors

Cited Authors

  • Aust, MR; Andrews, LG; Barrett, MJ; Norby-Slycord, CJ; Markert, ML

Published Date

  • October 1992

Published In

Volume / Issue

  • 51 / 4

Start / End Page

  • 763 - 772

PubMed ID

  • 1384322

Pubmed Central ID

  • 1384322

International Standard Serial Number (ISSN)

  • 0002-9297

Language

  • eng

Conference Location

  • United States