ABCMdb

PMID: 17942821

Shield JP, Flanagan SE, Mackay DJ, Harries LW, Proks P, Girard C, Ashcroft FM, Temple IK, Ellard S
Mosaic paternal uniparental isodisomy and an ABCC8 gene mutation in a patient with permanent neonatal diabetes and hemihypertrophy.
Diabetes. 2008 Jan;57(1):255-8. Epub 2007 Oct 17., [PubMed]

Sentences

No. Mutations Sentence Comment

5 ABCC8 p.Asn72Ser RESULTS-A paternally inherited activating mutation (N72S) in the ABCC8 gene was identified in the proband. Login to comment 51 ABCC8 p.Asn72Ser ABCC8 p.Asn72Ser The father was identified as being heterozygous for a missense mutation, N72S (c.215AϾG), while the proband`s leukocyte DNA showed mosaicism for the N72S mutation (Fig. 2B). Login to comment 52 ABCC8 p.Asn72Ser The N72S mutation was not found in 250 normal chromosomes, and the affected residue was conserved across species. Login to comment 53 ABCC8 p.Asn72Ser ABCC8 p.Asn72Ser ABCC8 p.Asn72Ser Quantification by real-time PCR (TaqMan assay) demonstrated that the N72S mutation was present at ϳ70% in leukocyte DNA and 50% in buccal cells. Login to comment 54 ABCC8 p.Asn72Ser The N72S mutation was not found in 250 normal chromosomes, and the affected residue was conserved across species. Login to comment 55 ABCC8 p.Asn72Ser ABCC8 p.Asn72Ser Genomic DNA from the father, who is heterozygous for the N72S mutation, was used in serial dilution to produce standard curves to determine linear range and accuracy of quantification (primer and probe sequences are available on request). Login to comment 57 ABCC8 p.Asn72Ser Genomic DNA from the father, who is heterozygous for the N72S mutation, was used in serial dilution to produce standard curves to determine linear range and accuracy of quantification (primer and probe sequences are available on request). Login to comment 59 ABCC8 p.Asn72Ser Functional studies in Xenopus oocytes (methods in 9,10) demonstrated that the N72S mutation results in a reduced sensitivity to inhibition by MgATP. Login to comment 60 ABCC8 p.Asn72Ser Half-maximal block of homozygous N72S channels was produced by 23 Ϯ 1 ␮mol/l ATP (n ϭ 10) compared with 15 Ϯ 1 ␮mol/l (n ϭ 6) for wild-type channels. Login to comment 62 ABCC8 p.Asn72Ser ABCC8 p.Asn72Ser Homozygous N72S channels were substantially blocked by the sulfonylurea tolbutamide in vitro (Fig. 3). Login to comment 63 ABCC8 p.Asn72Ser Half-maximal block of homozygous N72S channels was produced by 23 afe; 1 òe;mol/l ATP (n afd; 10) compared with 15 afe; 1 òe;mol/l (n afd; 6) for wild-type channels. Login to comment 65 ABCC8 p.Asn72Ser Homozygous N72S channels were substantially blocked by the sulfonylurea tolbutamide in vitro (Fig. 3). Login to comment 68 ABCC8 p.Asn72Ser efficacy of sulfonylureas in neonatal diabetes caused by KATP channel mutations (21), and the tolbutamide block of mutant N72S channels observed in functional studies, prompted a trial of the sulfonylurea glyburide. Login to comment 71 ABCC8 p.Asn72Ser efficacy of sulfonylureas in neonatal diabetes caused by KATP channel mutations (21), and the tolbutamide block of mutant N72S channels observed in functional studies, prompted a trial of the sulfonylurea glyburide. Login to comment 83 ABCC8 p.Asn72Ser The lack of a therapeutic response to sulfonyureas in our patient is puzzling, as the mutant N72S channels were blocked by tolbutamide in in vitro studies. Login to comment 86 ABCC8 p.Asn72Ser The lack of a therapeutic response to sulfonyureas in our patient is puzzling, as the mutant N72S channels were blocked by tolbutamide in in vitro studies. Login to comment 94 ABCC8 p.Asn72Ser Resting whole-cell KATP channel currents are slightly larger for homomeric N72S mutant channels and are blocked by sulfonylureas. Login to comment 95 ABCC8 p.Asn72Ser ABCC8 p.Asn72Ser Mean steady-state whole-cell KATP channel currents for wild-type (WT), homomeric (hom) N72S, and heterozygous (het) N72S channels, as indicated evoked by a voltage step from -10 to -30 mV before (Ⅺ, resting condition), after application of the metabolic inhibitor 3 mmol/l azide (o), and in the presence of 3 mmol/l azide plus 0.5 mmol/l tolbutamide (f). Login to comment 97 ABCC8 p.Asn72Ser Resting whole-cell KATP channel currents are slightly larger for homomeric N72S mutant channels and are blocked by sulfonylureas. Login to comment 98 ABCC8 p.Asn72Ser ABCC8 p.Asn72Ser Mean steady-state whole-cell KATP channel currents for wild-type (WT), homomeric (hom) N72S, and heterozygous (het) N72S channels, as indicated evoked by a voltage step from d1a;10 to d1a;30 mV before (ǧa;, resting condition), after application of the metabolic inhibitor 3 mmol/l azide (o), and in the presence of 3 mmol/l azide plus 0.5 mmol/l tolbutamide (f). Login to comment 100 ABCC8 p.Asn72Ser The level of mosaicism for the N72S mutation varied between leukocytes (ϳ70% mutation) and buccal cells (ϳ50% mutation). Login to comment 103 ABCC8 p.Asn72Ser The level of mosaicism for the N72S mutation varied between leukocytes (b03;70% mutation) and buccal cells (b03;50% mutation). Login to comment