chr17-7445158-G-A

Position:

• chr17-7445158-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000747.3(CHRNB1):​c.31G>A​(p.Gly11Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: CHRNB1 NM_000747.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.300

Genes affected

CHRNB1 (HGNC:1961): (cholinergic receptor nicotinic beta 1 subunit) The muscle acetylcholine receptor is composed of five subunits: two alpha subunits and one beta, one gamma, and one delta subunit. This gene encodes the beta subunit of the acetylcholine receptor. The acetylcholine receptor changes conformation upon acetylcholine binding leading to the opening of an ion-conducting channel across the plasma membrane. Mutations in this gene are associated with slow-channel congenital myasthenic syndrome. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNB1	NM_000747.3	c.31G>A	p.Gly11Arg	missense_variant	1/11	ENST00000306071.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNB1	ENST00000306071.7	c.31G>A	p.Gly11Arg	missense_variant	1/11	1	NM_000747.3	P1
CHRNB1	ENST00000572857.5	c.31G>A	p.Gly11Arg	missense_variant	1/6	4
CHRNB1	ENST00000574054.1	n.51G>A		non_coding_transcript_exon_variant	1/2	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1456862 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 724698

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital myasthenic syndrome 2A Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 27, 2020

Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with CHRNB1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with arginine at codon 11 of the CHRNB1 protein (p.Gly11Arg). The glycine residue is weakly conserved and there is a moderate physicochemical difference between glycine and arginine. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.55
BayesDel_addAF	Uncertain	0.024	T
BayesDel_noAF	Benign	-0.20
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Benign	0.15	T;.
Eigen	Benign	-0.026
Eigen_PC	Benign	0.042
FATHMM_MKL	Benign	0.64	D
M_CAP	Uncertain	0.14	D
MetaRNN	Uncertain	0.47	T;T
MetaSVM	Benign	-0.80	T
MutationAssessor	Uncertain	2.4	M;.
MutationTaster	Benign	0.65	D;D
PrimateAI	Uncertain	0.76	T
PROVEAN	Benign	-1.8	N;.
REVEL	Uncertain	0.45
Sift	Benign	0.11	T;.
Sift4G	Benign	0.32	T;T
Polyphen		0.58	P;.
Vest4		0.71
MutPred		0.42		Gain of methylation at G11 (P = 0.0263);Gain of methylation at G11 (P = 0.0263);
MVP		0.85
MPC		0.48
ClinPred		0.74	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.18
gMVP		0.61

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: rs1908543374; hg19: chr17-7348477;