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A high proportion of ADA point mutations associated with a specific alanine-to-valine substitution.

Publication ,  Journal Article
Markert, ML; Norby-Slycord, C; Ward, FE
Published in: Am J Hum Genet
September 1989

In 15%-20% of children with severe combined immunodeficiency (SCID), the underlying defect is adenosine deaminase (ADA) deficiency. The overall goal of our research has been to identify the precise molecular defects in patients with ADA-deficient SCID. In this study, we focused on a patient whom we found to have normal sized ADA mRNA by Northern analysis and an intact ADA structural gene by Southern analysis. By cloning and sequencing this patient's ADA cDNA, we found a C-to-T point mutation in exon 11. This resulted in the amino acid substitution of a valine for an alanine at position 329 of the ADA protein. Sequence analysis revealed that this mutation created a new BalI restriction site. Using Southern analyses, we were able to directly screen individuals to determine the frequency of this mutation. By combining data on eight families followed at our institution with data on five other families reported in the literature, we established that five of 13 patients (seven of 22 alleles) with known or suspected point mutations have this defect. This mutation was found to be associated with three different ADA haplotypes. This argues against a founder effect and suggests that the mutation is very old. In summary, a conservative amino acid substitution is found in a high proportion of patients with ADA deficiency; this can easily be detected by Southern analysis.

Duke Scholars

Published In

Am J Hum Genet

ISSN

0002-9297

Publication Date

September 1989

Volume

45

Issue

3

Start / End Page

354 / 361

Location

United States

Related Subject Headings

  • Valine
  • Nucleoside Deaminases
  • Mutation
  • Immunologic Deficiency Syndromes
  • Humans
  • Haplotypes
  • Genetics & Heredity
  • DNA Probes
  • DNA
  • Cloning, Molecular
 

Citation

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Chicago
ICMJE
MLA
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Markert, M. L., Norby-Slycord, C., & Ward, F. E. (1989). A high proportion of ADA point mutations associated with a specific alanine-to-valine substitution. Am J Hum Genet, 45(3), 354–361.
Markert, M. L., C. Norby-Slycord, and F. E. Ward. “A high proportion of ADA point mutations associated with a specific alanine-to-valine substitution.Am J Hum Genet 45, no. 3 (September 1989): 354–61.
Markert ML, Norby-Slycord C, Ward FE. A high proportion of ADA point mutations associated with a specific alanine-to-valine substitution. Am J Hum Genet. 1989 Sep;45(3):354–61.
Markert, M. L., et al. “A high proportion of ADA point mutations associated with a specific alanine-to-valine substitution.Am J Hum Genet, vol. 45, no. 3, Sept. 1989, pp. 354–61.
Markert ML, Norby-Slycord C, Ward FE. A high proportion of ADA point mutations associated with a specific alanine-to-valine substitution. Am J Hum Genet. 1989 Sep;45(3):354–361.
Journal cover image

Published In

Am J Hum Genet

ISSN

0002-9297

Publication Date

September 1989

Volume

45

Issue

3

Start / End Page

354 / 361

Location

United States

Related Subject Headings

  • Valine
  • Nucleoside Deaminases
  • Mutation
  • Immunologic Deficiency Syndromes
  • Humans
  • Haplotypes
  • Genetics & Heredity
  • DNA Probes
  • DNA
  • Cloning, Molecular