NM_000352.6:c.3989-9G>A
Variant summary
Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM2PP5_Very_Strong
The NM_000352.6(ABCC8):c.3989-9G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000185 in 1,614,150 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Consequence
NM_000352.6 intron
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 10 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000177 AC: 27AN: 152194Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.000326 AC: 82AN: 251406Hom.: 0 AF XY: 0.000316 AC XY: 43AN XY: 135884
GnomAD4 exome AF: 0.000185 AC: 271AN: 1461838Hom.: 0 Cov.: 34 AF XY: 0.000198 AC XY: 144AN XY: 727220
GnomAD4 genome AF: 0.000177 AC: 27AN: 152312Hom.: 0 Cov.: 33 AF XY: 0.000134 AC XY: 10AN XY: 74474
ClinVar
Submissions by phenotype
not provided Pathogenic:7
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This sequence change falls in intron 32 of the ABCC8 gene. It does not directly change the encoded amino acid sequence of the ABCC8 protein. This variant is present in population databases (rs151344623, gnomAD 0.6%). This variant has been observed in individual(s) with autosomal recessive familial hyperinsulinism (PMID: 7716548, 27754802). It is commonly reported in individuals of Ashkenazi Jewish ancestry (PMID: 8923011, 21716120). This variant is also known as 3992–9g→a. ClinVar contains an entry for this variant (Variation ID: 9088). Studies have shown that this variant alters mRNA splicing and is expected to lead to the loss of protein expression (PMID: 7716548). For these reasons, this variant has been classified as Pathogenic. -
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Published functional studies suggest that c.3989-9G>A activates a preexisting cryptic 3splice site within exon 33, resulting in out-of-frame product (Saint-Martin et al., 2021); In silico analysis supports a deleterious effect on splicing; This variant is associated with the following publications: (PMID: 25972930, 7716548, 8923011, 20672374, 27754802, 21716120, 25306193, 31980526, 31589614, 33726816, 33410562) -
Hyperinsulinemic hypoglycemia, familial, 1 Pathogenic:4
The c.3989-9G>A variant in ABCC8 has been reported in >10 individuals with hyperinsulinemic hypoglycemia (PMID: 25306193, 25972930, 16429405, 16860127, 27175728, 17378627, 11272143, 27754802), and has been identified In 0.6% (62/10366) or Ashkenazi Jewish chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs151344623). 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 (Variation ID: 9088) and has been interpreted as pathogenic by multiple sources. Of the many affected individuals, at least 3 were compound heterozygotes that carried a reported pathogenic variant in trans, and 4 of those were homozygotes, which increases the likelihood that the c.3989-9G>A variant is pathogenic (Variation ID: 188864, 9096; PMID: 16429405, 16860127, 17378627). RNAseq analysis performed on affected tissue shows a deletion of the first 20 nucleotides of exon 33 (PMID: 33410562). This variant is located in the 3’ splice region. Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive hyperinsulinemic hypoglycemia. ACMG/AMP Criteria applied: PM3_very_strong, PS3, PP3 (Richards 2015). -
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NM_000352.3(ABCC8):c.3989-9G>A is classified as pathogenic in the context of ABCC8-related familial hyperinsulinism. Sources cited for classification include the following: PMID 10447255, 7716548, 23345197, 11999683, 11272143, 24401662, 15579781, 21851374, 16860127 and 8923011. Classification of NM_000352.3(ABCC8):c.3989-9G>A is based on the following criteria: This is a well-established pathogenic variant in the literature that has been observed more frequently in patients with clinical diagnoses than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -
The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.029%). In silico tools predict the variant to alter splicing and produce an abnormal transcript (SpliceAI: 0.70). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least one similarly affected unrelated individual (PMID: 25306193) and co-segregate with the disease in at least one similarly affected relative/individual in the same family or similarly affected unrelated family (PMID: 27754802, 7716548). The variant has been reported at least twice as pathogenic with clinical assertions and evidence for the classification (ClinVar ID: VCV000009088). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -
Familial hyperinsulinism Pathogenic:2
Variant summary: ABCC8 c.3989-9G>A alters a nucleotide located at a position not widely known to affect splicing. Consensus agreement among computation tools predict no significant impact on normal splicing. Functional study shows that this variant leads to aberrant splicing, resulting in a 7-bp addition, a 20-bp deletion, or 30-bp deletion of exon 32 that encodes NBF-2 (nucleotide binding fold 2) of the protein (Thomas_1995). The variant allele was found at a frequency of 0.0015 in 294100 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in ABCC8 causing Congenital Hyperinsulinism (0.0015 vs 0.0034), allowing no conclusion about variant significance. c.3989-9G>A has been reported in the literature in multiple individuals affected with Congenital Hyperinsulinism (Thomas_1995, Tornovsky_2004, Nestorowicz_1996, Glaser_2011). These data indicate that the variant is very likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 7716548, 15579781, 8923011, 21716120). ClinVar contains an entry for this variant (Variation ID: 9088). Based on the evidence outlined above, the variant was classified as pathogenic. -
NG_008867.1(NM_001287174.1):c.3992-9G>A in the ABCC8 gene has an allele frequency of 0.006 in Ashkenazi Jewish subpopulation in the gnomAD database. This variant has been observed to segregate with familial hyperinsulinism and affect RNA splicing (PMID: 7716548). In addition, Gutgold et al. reported a male with recurrent hypoglycemia episodes and revealed a homozygosity for c.3992-9G>A (PMID: 27754802). Experimental studies have shown that this intronic change alters ABCC8 splicing (PMID: 7716548). Taken together, we interprete this variant as Pathogenic/Likely pathogenic. ACMG/AMP Criteria applied: PS4; PS3; PM3; PP4. -
Hyperinsulinemic hypoglycemia, familial, 1;C5394303:Diabetes mellitus, permanent neonatal 3 Pathogenic:1
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Type 2 diabetes mellitus Pathogenic:1
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Inborn genetic diseases Pathogenic:1
The c.3989-9G>A intronic alteration results from a G to A substitution 9 nucleotides before coding exon 33 of the ABCC8 gene. Based on the available evidence, the ABCC8 c.3989-9G>A alteration is classified as pathogenic for familial hyperinsulinemic hypoglycemia, but is unlikely to be causative of autosomal dominant ABCC8-related diabetes mellitus. This alteration has been reported in the homozygous and compound heterozygous states and in the heterozygous state on the paternal allele in multiple individuals with congenital hyperinsulinemic hypoglycemia (Del Roio Liberatore, 2015; Glaser, 2011; Gutgold, 2017; Nestorowicz, 1996; Thomas, 1995). This is also a common founder mutation in the Ashkenazi Jewish population (Glaser, 2011; Nestorowicz, 1996). This nucleotide position is not well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site. Based on the available evidence, this alteration is classified as pathogenic. -
Hereditary hyperinsulinism Pathogenic:1
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Type 2 diabetes mellitus;C0271714:Leucine-induced hypoglycemia;C1835887:Diabetes mellitus, transient neonatal, 2;C2931832:Hyperinsulinemic hypoglycemia, familial, 1;C5394303:Diabetes mellitus, permanent neonatal 3 Pathogenic:1
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ABCC8-related disorder Pathogenic:1
The ABCC8 c.3989-9G>A variant is predicted to interfere with splicing. This variant has been previously reported to be pathogenic for persistent hyperinsulinemic hypoglycemia due to defective splicing (Thomas et al. 1995. PubMed ID: 7716548; Nestorowicz et al. 1996. PubMed ID: 8923011). In Family 4 of the Thomas et al. study, this variant occurred in the homozygous state in two affected siblings and was heterozygous in both unaffected parents. In the Nestorowicz et al. study, out of the 23 probands who had this variant, 11 were homozygotes and 12 were heterozygotes. This variant is reported in 0.60% of alleles in individuals of Ashkenazi Jewish descent in gnomAD. In summary, this variant is interpreted as pathogenic. -
Leucine-induced hypoglycemia;C2931832:Hyperinsulinemic hypoglycemia, familial, 1 Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at