title: Mutations in the VNTR of the carboxyl-ester lipase gene (CEL) are a rare cause of monogenic diabetes.
abstract: We have previously shown that heterozygous single-base deletions in the carboxyl-ester lipase (CEL) gene cause exocrine and endocrine pancreatic dysfunction in two multigenerational families. These deletions were found in the first and fourth repeats of a variable number of tandem repeats (VNTR), which has proven challenging to sequence due to high GC-content and considerable length variation. We have therefore developed a screening method consisting of a multiplex PCR followed by fragment analysis. The method detected putative disease-causing insertions and deletions in the proximal repeats of the VNTR, and determined the VNTR-length of each allele. When blindly testing 56 members of the two families with known single-base deletions in the CEL VNTR, the method correctly assessed the mutation carriers. Screening of 241 probands from suspected maturity-onset diabetes of the young (MODY) families negative for mutations in known MODY genes (95 individuals from Denmark and 146 individuals from UK) revealed no deletions in the proximal repeats of the CEL VNTR. However, we found one Danish patient with a short, novel CEL allele containing only three VNTR repeats (normal range 7-23 in healthy controls). This allele co-segregated with diabetes or impaired glucose tolerance in the patient's family as six of seven mutation carriers were affected. We also identified individuals who had three copies of a complete CEL VNTR. In conclusion, the CEL gene is highly polymorphic, but mutations in CEL are likely to be a rare cause of monogenic diabetes.
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: Janniche
authors.initials: J
authors.lastname: Torsvik
authors.forename: Stefan
authors.initials: S
authors.lastname: Johansson
authors.forename: Anders
authors.initials: A
authors.lastname: Johansen
authors.forename: Jakob
authors.initials: J
authors.lastname: Ek
authors.forename: Jayne
authors.initials: J
authors.lastname: Minton
authors.forename: Helge
authors.initials: H
authors.lastname: Raeder
authors.forename: Sian
authors.initials: S
authors.lastname: Ellard
authors.forename: Andrew
authors.initials: A
authors.lastname: Hattersley
authors.forename: Oluf
authors.initials: O
authors.lastname: Pedersen
authors.forename: Torben
authors.initials: T
authors.lastname: Hansen
authors.forename: Anders
authors.initials: A
authors.lastname: Molven
authors.forename: Pål R
authors.initials: PR
authors.lastname: Njølstad
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D004252:DNA Mutational Analysis; D003718:Denmark; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005192:Family Health; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008049:Lipase / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics*; D009154:Mutation; D010375:Pedigree; D006113:United Kingdom
chemical_list: C054621:CEL protein, human; D008049:Lipase