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SGSM3

small G protein signaling modulator 3

Chromosome 22q13.1 HGNC:25228 Tier C
SGSM3 22q13.1 p arm q arm 22

SGSM3 is located on the long (q) arm of chromosome 22, at band 22q13.1. Arm ratio per GRCh38 - banding schematic.

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Overview

SGSM3 (small G protein signalling modulator 3) is located on chromosome 22 and belongs to a family of proteins that regulate small GTPases. Small GTPases act as molecular switches, cycling between active and inactive states to control processes such as intracellular transport, cytoskeletal dynamics, and signal relay. The SGSM3 protein is thought to influence these pathways by modulating GTPase activity, though the full scope of its cellular functions remains under investigation. Research has identified SGSM3 expression in multiple tissue types, suggesting it may contribute to fundamental cellular processes across different organ systems.

What the gene does

The SGSM3 protein functions as a regulator of small G protein signalling cascades. Small GTPases such as those in the Rab and Arf families coordinate membrane trafficking, vesicle formation, and organelle identity by switching between GTP-bound (active) and GDP-bound (inactive) conformations. Proteins like SGSM3 are believed to participate in this regulatory cycle, potentially acting as guanine nucleotide exchange factors or GTPase-activating proteins, though the precise biochemical mechanism remains an area of active research. By influencing GTPase activity, SGSM3 may help orchestrate the timing and localisation of cellular events including endocytosis, secretory pathway function, and signal transduction. The protein's involvement in these pathways suggests it plays a supporting role in maintaining normal cellular architecture and communication.

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Chromosome location

SGSM3 is positioned on the long arm of chromosome 22 at band 22q13.1. This chromosomal region contains multiple genes involved in various cellular processes. The specific exon structure and transcript variants of SGSM3 have not been extensively documented in public databases, reflecting the ongoing nature of research into this gene. The 22q13 region has been studied in relation to several genomic disorders, though SGSM3 itself has not been conclusively linked to a specific clinical phenotype at this time.

Protein structure

Domain architecture has not been experimentally characterised in detail for this protein. The SGSM3 protein's structural organisation and specific functional motifs await further biochemical and structural analysis. Predicted bioinformatic analyses may suggest potential interaction surfaces or regulatory regions, but these have not been validated through crystallography or other definitive methods.

Domain map · 749 amino acids
Rab-GAP TBC (114–305)Coiled coil (415–439)SH3 (480–539)RUN (555–718)Rab-GAP TBC114–305SH3480–539RUN555–7181~375749
Domain - independent functional unit
Region - functional region
🧬 Explore 3D structure on AlphaFold
UniProt:Q96HU1Length:749 aaStructure:AlphaFold

Key variants

Genetic variation in SGSM3 has been documented in population databases, though the clinical significance of most variants remains uncertain. Changes in the DNA sequence can range from single nucleotide substitutions to larger deletions or duplications. The inheritance pattern associated with SGSM3 variation may vary depending on the specific variant and its functional impact. Currently, most identified variants are classified as variants of uncertain significance, reflecting limited clinical and functional data.

The table below shows the top 1 pathogenic or likely-pathogenic variants currently classified in ClinVar for SGSM3.
View all on ClinVar →

Sample of pathogenic variants

1 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.

Variant (HGVS) Protein change Classification Evidence Associated condition
c.1576C>T
single nucleotide variant
p.Arg526Ter Pathogenic - Intellectual developmental disorder, autosomal recessive 84

Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.

Associated conditions

No specific inherited conditions have been definitively associated with pathogenic variants in SGSM3. The gene has not been included in UK NHS clinical gene panels, indicating that evidence linking it to a recognised disease state is not yet sufficient for routine diagnostic testing. As research progresses, a clearer picture of whether SGSM3 variants contribute to human disease may emerge.

No disease links recorded for this gene in our reference set.

UK clinical status

Frequently asked questions

What does the SGSM3 gene do?

SGSM3 encodes a protein thought to regulate small G protein signalling, which influences processes such as intracellular transport and cellular communication. The precise molecular mechanisms are still being researched.

Are there known diseases caused by SGSM3 variants?

Currently, no specific inherited conditions have been definitively linked to pathogenic variants in SGSM3. The gene is not included in NHS clinical diagnostic panels at this time.

Where is the SGSM3 gene located?

SGSM3 is located on chromosome 22 at band 22q13.1, on the long arm of the chromosome.

Educational content. This page is not medical or genetic advice, is not individually reviewed by a clinician for each reader, and should not replace a consultation with a qualified healthcare professional or genetic counsellor. If you are considering genetic testing or acting on a test result, book a consultation.
Data sources Last updated 17 April 2026. Content compiled from HGNC · MedlinePlus Genetics · ClinGen · Genomics England PanelApp · NHS National Genomic Test Directory · ClinVar · UniProt · AlphaFold .