FAM3B

protein-coding

FAM3 metabolism regulating signaling molecule B

Gene summary

Predicted to enable cytokine activity. Involved in insulin secretion. Located in extracellular exosome. [provided by Alliance of Genome Resources, Jul 2025]

Previous symbols:

C21orf11

MANE transcript

NM_058186.4

Inheritance

—

ClinVar variants

U:20B:4

Top phenotype

—

gnomAD constraint

pLI —, LoF o/e 0.96

Max pathogenic AF

—

Genomic locus

chr21:41,304,212-41,357,727

External References & Databases

Ensembl (ENSG00000183844)

Transcript & Mutation Effects

hg38 • Region Span ~53.5 kb

Loading mutation effect viewer...

GenCC Phenotypes & Disease Associations

Curated gene-disease validity assertions and inheritance patterns

No GenCC data available for this gene.

ClinVar Associated Diseases & Phenotypes

Reported disease conditions connected to FAM3B variants in ClinVar

2 Conditions Cataloged

not specifiedTotal: 15

not providedTotal: 4

ClinVar Variants & Pathogenicity by Type

Statistics based on transcript NM_058186.4. Only rare variants are included.

We include only reliable ClinVar variants with their consequences to MANE Select, MANE Plus Clinical transcripts, or transcripts with TSL equal to 1. Click a count to filter the variants table below.

Slight differences between displayed counts and ClinVar may occur due to a different transcript/consequence chosen by our variant effect predictor, or because we classify Benign/Likely benign as Likely benign and Pathogenic/Likely pathogenic as Likely pathogenic.

Effect	PathogenicP	Likely pathogenicLP	VUS	Likely benignLB	BenignB	Sum
synonymous			1 clinvar		2 clinvar	3
missense			14 clinvar	2 clinvar		16
nonsense			1 clinvar			1
start loss						0
frameshift						0
splice donor/acceptor (+/-2bp)			4 clinvar			4
Total	0	0	20	2	2	24

Loading ClinVar variants...

Transcript Catalog

Annotated transcript isoforms across RefSeq and Ensembl databases

Showing 4 of 15 transcripts

Transcript ID	Source	Protein ID	Coding Exons	MANE Status
NM_058186.4	RefSeq	NP_478066.3	8	MANE Select
ENST00000357985.7	Ensembl	ENSP00000350673.2	8	MANE Select
NM_206964.2	RefSeq	NP_996847.1	7	Standard
ENST00000398646.3	Ensembl	ENSP00000381641.3	7	Standard

Gene Ontology (GO) Annotations & Pathways

Biological processes, molecular functions, cellular components and pathways

Biological Process

apoptotic process
regulation of signaling receptor activity
insulin secretion
glucose homeostasis

Molecular Function

cytokine activity

Cellular Component

extracellular region
extracellular exosome

gnomAD Constraint

Source: gnomAD

Gene type: protein_coding
Transcript type: protein_coding
Transcript: ENST00000357985
Coding exons: 8
Length: 53220
Individuals with no LoFs: 125631
Homozygous LoFs: 0
Heterozygous LoFs: 117
Defined: 125748
p: 0.000465

	Z-Score	Observed	Expected	Observed/Expected	Mutation Rate	Total Possible
Missense	0.461	115	130	0.886	0.00000669	1534
Missense (PolyPhen)		43	46.297	0.92879		570
Synonymous	-0.517	53	48.4	1.09	0.00000301	434
Loss of Function	0.141	12	12.5	0.957	6.15e-7	153

Population LoF Frequency

Population	CAF	p-value	Status
African	0.00012	0.00012	rare
Latino/Admixed American	0.0017	0.0017	notable
Ashkenazi Jewish	0.00069	0.00069	rare
East Asian	0.00011	0.00011	rare
Finnish	0	0.0	absent
European (Non-Finnish)	0.00031	0.00030	rare
South Asian	0.00033	0.00033	rare
Other	0.00050	0.00049	rare

dbNSFP Gene Annotations

Source: dbNSFP

Function: FUNCTION: Induces apoptosis of alpha and beta cells in a dose- and time-dependent manner. {ECO:0000269|PubMed:16114871}.;

Recessive Scores

pRec: 0.0867

Intolerance Scores

LoFtool: 0.894
RVIS EVS: 0.24
RVIS percentile EVS: 69.21

Essentials

Essential (CRISPR): N
Essential (CRISPR2): N
Essential (gene trap): N
Indispensability pred.: N
Indispensability score: 0.129

Gene Damage Prediction

	All	Recessive	Dominant
Mendelian	Medium	Medium	Medium
Primary Immunodeficiency	Medium	Medium	Medium
Cancer	Medium	Medium	Medium