Deletion of exon 3 of the insulin receptor gene in a kindred with a familial form of insulin resistance

Journal Article · Sun May 01 04:00:00 EDT 1994 · Journal of Clinical Endocrinology and Metabolism

DOI:https://doi.org/10.1210/jc.78.5.1153· OSTI ID:450611

Wertheimer, E; Barbetti, F; Accili, D; Taylor, S I ^[1]; Litvin, Y; Ebstein, R P; Bennet, E R

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1. National Institutes of Health, Bethesda, MD (United States)

Molecular scanning techniques, such as denaturing gradient gel electrophoresis (DGGE), greatly facilitate screening candidate genes for mutations. The authors have used DGGE to screen for mutations in the insulin receptor gene in a family in which four of five daughters were affected by type A insulin resistance in association with acanthosis nigricans and hyperandrogenism. DGGE did not detect mutations in any of the 22 exons of the insulin receptor gene. Nevertheless, Southern blot analysis suggested that there was a deletion of exon 3 in the other paternal allele of the insulin receptor gene. Analysis of the father`s cDNA confirmed that exon 3 was deleted from mRNA molecules derived from one of his two alleles of the insulin receptor gene. Furthermore, the father was found to be hemizygous for a polymorphic sequence (GAC{sup Asp} at codon 234) in exon 3 that was not inherited by any of the five daughters. Instead, all five daughters inherited the paternal allele with the deletion mutation. They did not detect mutations in the mother`s insulin receptor gene. Furthermore, the clinical syndrome did not segregate with either of the mother`s two alleles of the insulin receptor gene. Although the youngest daughter inherited the mutant allele from her father, she was not clinically affected. The explanation for the incomplete penetrance is not known. These results emphasize the importance of specifically searching for deletion mutations when screening candidate genes for mutations. Furthermore, the existence of apparently asymptomatic carriers of mutations in the insulin receptor gene, such as the father in the present study, suggests that the prevalence of mutations in the insulin receptor gene may be higher than would be predicted on the basis of the observed prevalence of patients with extreme insulin resistance. 34 refs., 6 figs., 1 tab.

• OSTI ID: 450611
• Journal Information: Journal of Clinical Endocrinology and Metabolism, Journal Name: Journal of Clinical Endocrinology and Metabolism Journal Issue: 5 Vol. 78; ISSN JCEMAZ; ISSN 0021-972X
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
DIABETES MELLITUS
ETIOLOGY
GENE MUTATIONS
RECEPTORS