Transmembrane Protein 38B

Alternative Names

  • TMEM38B
  • Trimeric Intracellular Cation Channel Type B
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OMIM Number




Uniprot ID



82,089 bases

No. of Exons


No. of isoforms


Protein Name

Trimeric intracellular cation channel type B

Molecular Mass

32510 Da

Amino Acid Count


Genomic Location


Gene Map Locus


The TMEM38B gene encodes the trimeric intracellular cation channel type B (TRIC-B) protein that functions in the maintenance of intracellular calcium release.  These channels are localized predominantly to the sarco/endoplasmatic reticulum, where they function as counter ion channels that synchronize with ryanodine receptor-mediated Ca2+ release. 

Mutations in this gene are associated with Osteogenesis imperfecta, type XIV (OI14).

Epidemiology in the Arab World

View Map
Variant NameCountryGenomic LocationClinvar Clinical SignificanceCTGA Clinical Significance Condition(s)HGVS ExpressionsdbSNPClinvar
NM_018112.3:c.457_542+2delSaudi ArabiaNC_000009.12:g.105722536_105722623delPathogenicOsteogenesis Imperfecta, Type XIVNG_032971.1:g.33012_33099del; NM_018112.3:c.457_542+2del

Other Reports


Volodarsky et al (2013) studied three unrelated Bedouin consanguineous families with osteogenesis imperfecta.  Analysis with microsatellite markers did not show homozygosity at any of the known OI loci.  Genome wide linkage analysis was performed, and homozygosity by descent analysis identified a 4.8 Mb region on chromosome 9q, and a 2Mb interval within this region that was common between all the patients.  This suggested a common ancestral origin for this locus.  DNA from one of the patients was put through whole exome sequencing, thus uncovering a single mutation in the TMEM3B gene, which was at the abovementioned position.  This mutation (c.455_542del; p.Gly152Alafs*5) resulted in the deletion of exon 4 leading to a truncated protein.  QRT-PCR detected a fourfold reduction in the TMEM38B mRNA levels in the patients when compared to controls.  All patients in this study were found to have the same homozygous mutation in the TMEM38B gene, while all parents were found to be heterozygous carriers.

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