7-75986867-T-G

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BS1_Supporting BS2

The NM_031925.3(TMEM120A):c.*305A>C variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00229 in 580,252 control chromosomes in the GnomAD database, including 13 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0066 (11 hom., cov: 34)
  • Exomes 𝑓: 0.00076 (2 hom.)
• Consequence: TMEM120A NM_031925.3 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.47

Genes affected

TMEM120A (HGNC:21697): (transmembrane protein 120A) Predicted to enable ion channel activity. Involved in fat cell differentiation; protein heterooligomerization; and protein homooligomerization. Predicted to be located in plasma membrane. Predicted to be active in membrane. [provided by Alliance of Genome Resources, Apr 2022]

POR (HGNC:9208): (cytochrome p450 oxidoreductase) This gene encodes an endoplasmic reticulum membrane oxidoreductase that is essential for multiple metabolic processes, including reactions catalyzed by cytochrome P450 proteins for metabolism of steroid hormones, drugs and xenobiotics. The encoded protein has a flavin adenine dinucleotide (FAD)-binding domain and a flavodoxin-like domain which bind two cofactors, FAD and FMN, that allow it to donate electrons directly from NADPH to all microsomal P450 enzymes. Mutations in this gene cause a complex set of disorders, including apparent combined P450C17 and P450C21 deficiency, amenorrhea and disordered steroidogenesis, congenital adrenal hyperplasia and Antley-Bixler syndrome, that resemble those caused by defects in steroid metabolizing enzymes such as aromatase, 21-hydroxylase, and 17 alpha-hydroxylase. [provided by RefSeq, Aug 2020]

ACMG classification

Verdict is Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.91).
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0066 (1005/152336) while in subpopulation AFR AF= 0.0225 (934/41576). AF 95% confidence interval is 0.0213. There are 11 homozygotes in gnomad4. There are 476 alleles in male gnomad4 subpopulation. Median coverage is 34. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High Homozygotes in GnomAd at 11 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMEM120A	NM_031925.3	c.*305A>C		3_prime_UTR_variant	12/12	ENST00000493111.7
POR	NM_001395413.1			downstream_gene_variant		ENST00000461988.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMEM120A	ENST00000493111.7	c.*305A>C		3_prime_UTR_variant	12/12	1	NM_031925.3	P1
POR	ENST00000461988.6			downstream_gene_variant		1	NM_001395413.1	P4

Frequencies

GnomAD3 genomes AF: 0.00659 AC: 1003 AN: 152218 Hom.: 11 Cov.: 34

Gnomad AFR AF: 0.0225

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00366

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: 0.0000441

Gnomad OTH AF: 0.00575

GnomAD4 exome AF: 0.000759 AC: 325 AN: 427916 Hom.: 2 Cov.: 0 AF XY: 0.000617 AC XY: 138 AN XY: 223748

Gnomad4 AFR exome AF: 0.0193

Gnomad4 AMR exome AF: 0.00156

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000511

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000230

Gnomad4 OTH exome AF: 0.00227

GnomAD4 genome AF: 0.00660 AC: 1005 AN: 152336 Hom.: 11 Cov.: 34 AF XY: 0.00639 AC XY: 476 AN XY: 74490

Gnomad4 AFR AF: 0.0225

Gnomad4 AMR AF: 0.00366

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00569

Alfa AF: 0.00604 Hom.: 0

Bravo AF: 0.00720

Asia WGS AF: 0.00144 AC: 5 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital adrenal hyperplasia due to cytochrome P450 oxidoreductase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.91
Cadd	Benign	0.56
Dann	Benign	0.62

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs41302351; hg19: chr7-75616185;