POMT1

Chr 9AR

protein O-mannosyltransferase 1

Also known as: LGMD2K, LGMDR11, MDDGA1, MDDGB1, MDDGC1, RT

The protein encoded by POMT1 is an endoplasmic reticulum O-mannosyltransferase that functions with POMT2 to glycosylate dystroglycan, which is essential for muscle and brain development. Autosomal recessive mutations cause a spectrum of dystroglycanopathies ranging from severe Walker-Warburg syndrome with brain and eye malformations to milder limb-girdle muscular dystrophy. The pathogenic mechanism involves defective glycosylation of alpha-dystroglycan, disrupting its binding to extracellular matrix proteins.

OMIMResearchSummary from RefSeq, OMIM, UniProt
LOFmechanismARLOEUF 0.933 OMIM phenotypes
Clinical SummaryPOMT1
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Gene-Disease Validity (ClinGen)
myopathy caused by variation in POMT1 · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
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Clinical Trials
1 active or recruiting trial — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
0.93LOEUF
pLI 0.000
Z-score 1.92
OE 0.70 (0.530.93)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
0.62Z-score
OE missense 0.92 (0.841.00)
385 obs / 420.6 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.70 (0.530.93)
00.351.4
Missense OE0.92 (0.841.00)
00.61.4
Synonymous OE1.09
01.21.6
LoF obs/exp: 33 / 47.3Missense obs/exp: 385 / 420.6Syn Z: -0.94
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitivePOMT1-related muscular dystrophy-dystroglycanopathy congenital with brain and eye anomaliesLOFAR

Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.

DN
0.6356th %ile
GOF
0.4678th %ile
LOF
0.3842th %ile

The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.

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

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

POMT1 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold
Clinical Literature
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