Is ABCC8 p.Leu556= (c.1668C>T) pathogenic?

ABCC8 p.Leu556= (c.1668C>T) is classified Conflicting classifications of pathogenicity in ABCC8 (ClinVar, Conflicting submitters, 2 submitters; last evaluated 2024-11-21). Ultra-rare (popmax 0.0122%, eas); Associated with transient neonatal diabetes mellitus.

What condition is associated with ABCC8 p.Leu556= (c.1668C>T)?

ABCC8 p.Leu556= (c.1668C>T) is associated with transient neonatal diabetes mellitus, maturity-onset diabetes of the young (ClinVar).

How common is ABCC8 p.Leu556= (c.1668C>T) in the general population?

ABCC8 p.Leu556= (c.1668C>T) is ultra-rare (popmax 0.0122%, eas) (gnomAD).

ABCC8 p.Leu556=

c.1668C>T · rs1287759139 · VCV727590

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0122%, eas)

Conditions

transient neonatal diabetes mellitus

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 4.3	GERP -2, phastCons 1
Overall
CADD	13.25	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0122% East Asian · 5/41,062 alleles

Filtering AF 0.00477% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00308%

Overall 0.000571% 8/1,400,598 alleles · ultra-rare

Ancestry group	Frequency	1 in
East Asiangrpmax	0.0122%	8,212
Remaining individualsnot grpmax-eligible	0.00332%	30,107
European (non-Finnish)	8.71e-05%	1,147,492

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: ABCC8
Protein: p.Leu556=
Coding: c.1668C>T
MANE Select: NM_000352
dbSNP: rs1287759139
Type: single nucleotide variant
Location: chr11:17432207 (GRCh38)
Gene constraint: LOEUF 0.829 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 82.56 · 8 PDB
Residue 556: an α-helix; the abc transmembrane type-1 1 domain

Full ABCC8 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

transient neonatal diabetes mellitus — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: maturity-onset diabetes of the young

Similar variants

ABCC8 p.Leu556Phe Uncertain significance ★★ ⚠ same residue
ABCC8 c.2116+2T>C Pathogenic/Likely pathogenic ★★ same condition
ABCC8 c.3868-1G>A Pathogenic/Likely pathogenic ★★ same condition
ABCC8 c.3989-9G>A Pathogenic ★★ same condition
ABCC8 c.4308-2A>G Pathogenic/Likely pathogenic ★★ same condition
ABCC8 p.Arg1379His Pathogenic/Likely pathogenic ★★ same condition
ABCC8 p.Arg1538Gln Pathogenic/Likely pathogenic ★★ same condition
ABCC8 p.Gly228Asp Pathogenic/Likely pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/abcc8-p-leu556 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown