Is HGD p.Ala2= (c.6T>A) pathogenic?

HGD p.Ala2= (c.6T>A) is classified Likely benign in HGD (ClinVar, Multiple submitters, 2 submitters; last evaluated 2021-11-29). Very rare (popmax 0.00667%, afr); Associated with alkaptonuria.

What condition is associated with HGD p.Ala2= (c.6T>A)?

HGD p.Ala2= (c.6T>A) is associated with alkaptonuria (ClinVar).

How common is HGD p.Ala2= (c.6T>A) in the general population?

HGD p.Ala2= (c.6T>A) is very rare (popmax 0.00667%, afr) (gnomAD).

How is Alkaptonuria inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

HGD p.Ala2=

c.6T>A · rs1308413187 · VCV1626835

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00667%, afr)

Conditions

alkaptonuria

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 -6	GERP -5.2
Overall
CADD	0.24	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00667% African / African-American · 5/74,908 alleles

Filtering AF 0.00255% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00161%

Overall 0.00329% 5/152,178 alleles · very rare

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: HGD
Protein: p.Ala2=
Coding: c.6T>A
MANE Select: NM_000187
dbSNP: rs1308413187
Type: single nucleotide variant
Location: chr3:120682106 (GRCh38)
Gene constraint: LOEUF 1.199 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 96.85 · 2 PDB

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

Disease context

alkaptonuria — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Alkaptonuria (Orphanet):

Inheritance: Autosomal recessive
Onset: Adult, Infancy
Prevalence: 1-9 / 1 000 000 (Worldwide)

Similar variants

HGD c.1007-2A>T Pathogenic ★★ same condition
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HGD c.15+1G>A Pathogenic/Likely pathogenic ★★ same condition
HGD c.16-1G>A Pathogenic ★★ same condition
HGD c.342+1G>A Pathogenic/Likely pathogenic ★★ same condition
HGD c.342+1G>T Pathogenic ★★ same condition
HGD c.342+3A>C Pathogenic/Likely pathogenic ★★ same condition
HGD c.469+1G>C 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/hgd-p-ala2 (accessed [today's date]).

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