LMBRD1

Chr 6

LMBR1 domain containing 1

Also known as: C6orf209, LMBD1, MAHCF, NESI

NCBI Gene: 55788 ENSG00000168216 UniProt: Q9NUN5

The LMBRD1 protein functions as a lysosomal membrane chaperone that exports cobalamin (vitamin B12) from lysosomes to the cytosol by forming a complex with ABCD4 and MMACHC transporters. Mutations cause methylmalonic aciduria and homocystinuria (cblF and cblJ types), disorders of vitamin B12 metabolism that typically present in infancy with developmental delay, failure to thrive, and megaloblastic anemia. This condition follows autosomal recessive inheritance.

GeneReviews ResearchSummary from RefSeq, OMIM, UniProt

This gene encodes a lysosomal membrane protein that may be involved in the transport and metabolism of cobalamin. This protein also interacts with the large form of the hepatitis delta antigen and may be required for the nucleocytoplasmic shuttling of the hepatitis delta virus. Mutations in this gene are associated with the vitamin B12 metabolism disorder termed, homocystinuria-megaloblastic anemia complementation type F.[provided by RefSeq, Oct 2009]

GeneReviews ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtMethylmalonic aciduria and homocystinuria, cblF type

Clinical highlights

Gene-disease validity (ClinGen)

methylmalonic aciduria and homocystinuria type cblF · ARDefinitivesufficient evidence for diagnostic panels

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

0.93

LOEUF

LOF

Mechanism· G2P

📖

GeneReview available — LMBRD1