2-174748733-TGT-CCG

Variant names:

• chr2-174748733-TGT-CCG
• NM_000079.4:c.1087_1089delACAinsCGG
• CHRNA1 p.Thr363Arg

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP2

The NM_000079.4(CHRNA1):​c.1087_1089delACAinsCGG​(p.Thr363Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T363I) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: CHRNA1 NM_000079.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.22
• Publications: 0 publications found

Genes affected

CHRNA1 (HGNC:1955): (cholinergic receptor nicotinic alpha 1 subunit) The muscle acetylcholine receptor consiststs of 5 subunits of 4 different types: 2 alpha subunits and 1 each of the beta, gamma, and delta subunits. This gene encodes an alpha subunit that plays a role in acetlycholine binding/channel gating. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Nov 2012]

CHRNA1 Gene-Disease associations (from GenCC):

• congenital myasthenic syndrome 1A

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• myasthenic syndrome, congenital, 1B, fast-channel

  Inheritance: AD, AR Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• lethal multiple pterygium syndrome

  Inheritance: AR Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), Orphanet
• postsynaptic congenital myasthenic syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000236449 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 16 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Gene score misZ: 0.72157 (below the threshold of 3.09). Trascript score misZ: 1.6771 (below the threshold of 3.09). GenCC associations: The gene is linked to myasthenic syndrome, congenital, 1B, fast-channel, congenital myasthenic syndrome 1A, lethal multiple pterygium syndrome, postsynaptic congenital myasthenic syndrome.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000079.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA1	NM_000079.4	MANE Select	c.1087_1089delACAinsCGG	p.Thr363Arg	missense	N/A	NP_000070.1	Q53SH4
	CHRNA1	NM_001039523.3		c.1162_1164delACAinsCGG	p.Thr388Arg	missense	N/A	NP_001034612.1	P02708-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA1	ENST00000348749.9	TSL:1 MANE Select	c.1087_1089delACAinsCGG	p.Thr363Arg	missense	N/A	ENSP00000261008.5	P02708-2
	ENSG00000236449	ENST00000442996.1	TSL:1	n.321+18909_321+18911delTGTinsCCG		intron	N/A
	CHRNA1	ENST00000261007.9	TSL:2	c.1162_1164delACAinsCGG	p.Thr388Arg	missense	N/A	ENSP00000261007.5	P02708-1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		3.2

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr2-175613461;