Pathogenic, no assertion criteria provided | clinical testing | Genetic Services Laboratory, University of Chicago | Jun 21, 2021 | DNA sequence analysis of the ABCC8 gene demonstrated a sequence change, c.2506C>T, which results in the creation of a premature stop codon at amino acid position 836, p.Arg836*. This pathogenic sequence change is predicted to result in an abnormal transcript, which may be degraded, or may lead to the production of a truncated ABCC8 protein with potentially abnormal function. This pathogenic sequence change has previously been described in a patients with both diffuse and focal ABCC8-related hyperinsulinism (PMIDs: 15579781,26379717, 25765446). Functional studies have also demonstrated that this sequence change may impact protein function (PMID: 15579781). - |
Pathogenic, criteria provided, single submitter | curation | Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard | Aug 16, 2023 | The p.Arg836Ter variant in ABCC8 has been reported in at least 11 individuals with congenital hyperinsulinism (PMID: 30386300, 26740944, 17378627, 26379717, 28701683, 23345197, 25765446, 23301914, 21422196), and has been identified in 0.03% (12/35140) of Latino/Admixed American chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs72559722). Although this variant has been seen in the general population in a heterozygous state, its frequency is not high enough to rule out a pathogenic role. This variant has also been reported in ClinVar (VariationID: 188915) as pathogenic or likely pathogenic by 11 submitters. Of the 11 affected individuals, 1 of those was a homozygote and 5 were compound heterozygotes that carried a reported pathogenic or likely pathogenic variant in trans or with unknown phase, which increases the likelihood that the p.Arg836Ter variant is pathogenic (Variation ID: 188864, 939498; PMID: 26740944, 26379717, 28701683, 23345197, 25765446, 21422196). In vitro functional studies provide some evidence that the p.Arg836Ter variant may slightly impact protein function (PMID: 15579781). However, these types of assays may not accurately represent biological function. This nonsense variant leads to a premature termination codon at position 836, which is predicted to lead to a truncated or absent protein. Loss of function of the ABCC8 gene is an established disease mechanism in autosomal recessive hyperinsulinemic hypoglycemia. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive hyperinsulinemic hypoglycemia. ACMG/AMP Criteria applied: PVS1, PM3_very-strong, PS3_supporting (Richards 2015). - |
Likely pathogenic, criteria provided, single submitter | literature only | Counsyl | Aug 09, 2014 | - - |
Pathogenic, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Dec 16, 2019 | Variant summary: ABCC8 c.2506C>T (p.Arg836X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 6.1e-05 in 246774 control chromosomes (gnomAD). This frequency is not higher than expected for a pathogenic variant in ABCC8 causing Congenital Hyperinsulinism (6.1e-05 vs 0.0034). c.2506C>T has been reported in the literature, in compound heterozygous and homozygous state, in individuals affected with Congenital Hyperinsulinism (Tornovsky_2004, Yorifuji_2011). These data indicate that the variant is very likely to be associated with disease. Experimental evidence evaluating an impact on protein function demonstrated the variant severely impacts trafficking of the channel to the plasma membrane (it did not reach the plasma membrane at all), which in turn causes a substantial defect in channel activity (Tornovsky_2004). Five ClinVar submitters (evaluation after 2014) cite the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. - |
Pathogenic, criteria provided, single submitter | clinical testing | Rady Children's Institute for Genomic Medicine, Rady Children's Hospital San Diego | Mar 29, 2019 | This nonsense variant is predicted to result in loss of normal protein function. The variant has been previously reported in ClinVar as likely pathogenic (Variation ID: 188915). This variant has been described in the heterozygous, compound heterozygous, and homozygous state in diffuse and focal congenital hyperinsulinism (PMID: 23067144, 23345197, 23301914, 26379717, 29644095). It is present in the heterozygous state in the gnomAD population database at a frequency of 0.00006 (17/272624) and thus is presumed to be rare. The c.2506C>T (p.Arg836Ter) variant is predicted by multiple in silico tools to have a deleterious effect on protein function. Based on the available evidence, the c.2506C>T (p.Arg836Ter) variant is classified as pathogenic. - |
Likely pathogenic, criteria provided, single submitter | research | Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic | May 21, 2024 | This variant is found to be a potent High impact, deleterious variant with a CADD score of 40 and sufficient recent scientific evidence for both gene and variant correlation with the condition. Hence, this variant is reclassified as Likely pathogenic. - |