Is ALG6 c.816+4T>C pathogenic?

ALG6 c.816+4T>C is classified Uncertain significance in ALG6 (ClinVar, Single submitter, 1 submitter; last evaluated 2022-08-09). Very rare (popmax 0.00668%, eas); Associated with ALG6-congenital disorder of glycosylation 1C.

What condition is associated with ALG6 c.816+4T>C?

ALG6 c.816+4T>C is associated with ALG6-congenital disorder of glycosylation 1C (ClinVar).

How common is ALG6 c.816+4T>C in the general population?

ALG6 c.816+4T>C is very rare (popmax 0.00668%, eas) (gnomAD).

How is ALG6-CDG inherited?

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

ALG6 c.816+4T>C

rs762931650 · VCV1415420

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00668%, eas)

Conditions

ALG6-congenital disorder of glycosylation 1C

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
Splice region	donor +4	donor splice region (+4, within the first 6 intronic nt) · inside the BP7-excluded zone
SpliceAI	<0.2	all four deltas below 0.2 · T>A here scores Δ0.38 · evaluated, not missing
Constraint at this position
Conservation	phyloP -1.9	GERP -4.2
Non-coding constraint	Z 3.27	1 kb window · o/e 0.75 · regional · uncalibrated
Overall
CADD	8.025	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00668% East Asian · 3/44,890 alleles

Filtering AF 0.00177% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000891%

Overall 0.00031% 5/1,613,962 alleles · very rare

Ancestry group	Frequency	1 in
East Asiangrpmax	0.00668%	14,963
Admixed American	0.00167%	60,006
South Asian	0.0011%	91,088

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: ALG6
Coding: c.816+4T>C
MANE Select: NM_013339
dbSNP: rs762931650
Type: single nucleotide variant
Location: chr1:63412065 (GRCh38)
Gene constraint: LOEUF 0.892 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 93.08

Full ALG6 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

ALG6-congenital disorder of glycosylation 1C — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For ALG6-CDG (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

ALG6 c.1128-1G>A Likely pathogenic ★★ same condition
ALG6 c.1128-2A>C Likely pathogenic ★★ same condition
ALG6 c.1326+1G>A Pathogenic/Likely pathogenic ★★ same condition
ALG6 c.257+5G>A Pathogenic/Likely pathogenic ★★ same condition
ALG6 c.429+1G>T Likely pathogenic ★★ same condition
ALG6 c.495-2A>G Likely pathogenic ★★ same condition
ALG6 c.495-2A>T Likely pathogenic ★★ same condition
ALG6 c.680+1G>A 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/alg6-c-816-plus-4t-c (accessed [today's date]).

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