9-105694663-G-A

Variant names:

• chr9-105694663-G-A
• rs1358305421
• NM_018112.3:c.3G>A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PVS1_Supporting PM2

The NM_018112.3(TMEM38B):​c.3G>A​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,613,186 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TMEM38B NM_018112.3 start_lost
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.51

Genes affected

TMEM38B (HGNC:25535): (transmembrane protein 38B) This gene encodes an intracellular monovalent cation channel that functions in maintenance of intracellular calcium release. Mutations in this gene may be associated with autosomal recessive osteogenesis. [provided by RefSeq, Oct 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PVS1: Start lost variant, no pathogenic variants between lost start and next in-frame start position. Next in-frame start position is after 17 codons. Genomic position: 105694709. Lost 0.056 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TMEM38B	NM_018112.3	c.3G>A	p.Met1?	start_lost	Exon 1 of 6	ENST00000374692.8	NP_060582.1
TMEM38B	XM_011518831.3	c.3G>A	p.Met1?	start_lost	Exon 1 of 7		XP_011517133.1
TMEM38B	XM_011518832.4	c.3G>A	p.Met1?	start_lost	Exon 1 of 4		XP_011517134.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TMEM38B	ENST00000374692.8	c.3G>A	p.Met1?	start_lost	Exon 1 of 6	1	NM_018112.3	ENSP00000363824.3
TMEM38B	ENST00000434214	c.-276G>A		5_prime_UTR_variant	Exon 1 of 3	2		ENSP00000403026.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152128 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461058 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726864

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152128 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 74318

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000843 Hom.: 0

Bravo AF: 0.0000151

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Jan 20, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TMEM38B c.3G>A (p.Met1Ile) alters the initiation codon and is predicted to result either in absence of the protein or truncation of the encoded protein due to translation initiation at a downstream codon. The next downstream in-frame ATG start site is at codon 115 (exon 3). No other pathogenic variants been reported in HGMD or ClinVar that are located 5' of the next downstream putative in-frame start codon. Two of three in-silico tools predict a benign effect of the variant on protein function. The variant was absent in 250324 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.3G>A in individuals affected with Osteogenesis Imperfecta and no experimental evidence demonstrating its impact on protein function have been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Additionally, the variant has a non-damaging PoStaL score (0.192 compared to 0.4815 which corresponds to a 95% specificity in the test set [Takata_2021]). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Uncertain	0.087	D
BayesDel_noAF	Benign	-0.11
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.18	T
Eigen	Benign	0.10
Eigen_PC	Benign	0.16
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.79	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Benign	-0.99	T
PROVEAN	Benign	-1.7	N
REVEL	Benign	0.21
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.47	P
Vest4		0.76
MutPred		1.0		Gain of catalytic residue at M1 (P = 0.0222);
MVP		0.17
ClinPred		0.99	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.93
gMVP		0.68

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1358305421; hg19: chr9-108456944;