Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1PM2PM5PP3_StrongPP5
The NM_000352.6(ABCC8):c.4450G>A(p.Gly1484Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G1484V) has been classified as Pathogenic.
ABCC8 (HGNC:59): (ATP binding cassette subfamily C member 8) The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the MRP subfamily which is involved in multi-drug resistance. This protein functions as a modulator of ATP-sensitive potassium channels and insulin release. Mutations in the ABCC8 gene and deficiencies in the encoded protein have been observed in patients with hyperinsulinemic hypoglycemia of infancy, an autosomal recessive disorder of unregulated and high insulin secretion. Mutations have also been associated with non-insulin-dependent diabetes mellitus type II, an autosomal dominant disease of defective insulin secretion. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Jul 2020]
Verdict is Pathogenic. Variant got 11 ACMG points.
PM1
In a domain ABC transporter 2 (size 234) in uniprot entity ABCC8_HUMAN there are 33 pathogenic changes around while only 3 benign (92%) in NM_000352.6
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr11-17394360-C-A is described in Lovd as [Pathogenic].
PP3
MetaRNN computational evidence supports a deleterious effect, 0.993
PP5
Variant 11-17394361-C-T is Pathogenic according to our data. Variant chr11-17394361-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 434044.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Pathogenic=1}.
Genetic Services Laboratory, University of Chicago
Feb 11, 2016
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Maturity onset diabetes mellitus in young Uncertain:1
Uncertain significance, criteria provided, single submitter
research
Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic
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Mutations in ABCC8 gene are associated with both neonatal diabetes mellitus as well as MODY. Patients with this mutation may have a better response to sulfonylureas. However, no sufficient evidence is found to ascertain the role of this particular variant ( rs1554904102) in MODY yet. -
Transitory neonatal diabetes mellitus Uncertain:1
Uncertain significance, criteria provided, single submitter
research
Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic
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Mutations in ABCC8 gene are associated with both neonatal diabetes mellitus as well as MODY. Patients with this mutation may have a better response to sulfonylureas. However, no sufficient evidence is found to ascertain the role of this particular variant ( rs1554904102 ) in neonatal diabetes yet. -