SLC35D2

Chr 9

solute carrier family 35 member D2

Also known as: HFRC1, SQV7L, UGTrel8, hfrc

The protein transports UDP-N-acetylglucosamine and UDP-glucose from the cytosol into the Golgi lumen, supplying donor substrates essential for heparan sulfate synthesis and other glycosylation processes. Mutations in this gene cause congenital disorder of glycosylation type IIx, which presents with intellectual disability, seizures, and dysmorphic features, following an autosomal recessive inheritance pattern. The gene shows very low constraint against loss-of-function variants (pLI near zero), consistent with the recessive disease mechanism.

OMIMResearchSummary from RefSeq, UniProt
MultiplemechanismLOEUF 1.60
Clinical SummarySLC35D2
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
1.60LOEUF
pLI 0.000
Z-score -0.31
OE 1.08 (0.751.60)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
0.49Z-score
OE missense 0.89 (0.781.02)
143 obs / 160.6 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE1.08 (0.751.60)
00.351.4
Missense OE0.89 (0.781.02)
00.61.4
Synonymous OE0.91
01.21.6
LoF obs/exp: 18 / 16.6Missense obs/exp: 143 / 160.6Syn Z: 0.58
DN
0.76top 25%
GOF
0.75top 25%
LOF
0.2582th %ile

This gene has evidence for multiple mechanisms of pathogenicity (dominant-negative and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to dominant-negative as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

DNprediction above median
GOFprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

SLC35D2 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC