TMTC1

Chr 12

transmembrane O-mannosyltransferase targeting cadherins 1

Also known as: ARG99, OLF, TMTC1A

NCBI Gene: 83857 ENSG00000133687 UniProt: Q8IUR5 OMIM: 615855

The TMTC1 protein transfers mannose residues to serine and threonine residues on cadherins and other proteins in the endoplasmic reticulum, playing a critical role in O-linked mannosylation. Mutations cause cobblestone lissencephaly-4 with microcephaly and profound intellectual disability, following an autosomal recessive inheritance pattern. This gene shows moderate constraint against loss-of-function variants, with the associated phenotype typically presenting in the neonatal period with severe brain malformations.

OMIM ResearchSummary from RefSeq, UniProt

Enables dolichyl-phosphate-mannose-protein mannosyltransferase activity. Involved in protein O-linked glycosylation via mannose. Predicted to be located in endoplasmic reticulum and membrane. [provided by Alliance of Genome Resources, Jun 2026]

OMIM ResearchGenerating clinical summary…

Active trials

Pubs (1 yr)

—

P/LP submissions

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P/LP missense

0.71

LOEUF

Multiple*

Mechanism· predicted