chr12-4810685-C-T

Position:

• chr12-4810685-C-T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Moderate BS2

The NM_002235.5(KCNA6):​c.644C>T​(p.Ser215Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000041 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: KCNA6 NM_002235.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.61

Genes affected

KCNA6 (HGNC:6225): (potassium voltage-gated channel subfamily A member 6) Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class. The coding region of this gene is intronless, and the gene is clustered with genes KCNA1 and KCNA5 on chromosome 12. [provided by RefSeq, Jul 2008]

GALNT8 (HGNC:4130): (polypeptide N-acetylgalactosaminyltransferase 8) This gene encodes a member of the UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-T) family of enzymes. GalNAc-Ts initiate mucin-type O-linked glycosylation in the Golgi apparatus by catalyzing the transfer of GalNAc to serine and threonine residues on target proteins. They are characterized by an N-terminal transmembrane domain, a stem region, a lumenal catalytic domain containing a GT1 motif and Gal/GalNAc transferase motif, and a C-terminal ricin/lectin-like domain. GalNAc-Ts have different, but overlapping, substrate specificities and patterns of expression. [provided by RefSeq, Jul 2008]

KCNA6 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.15484655).
• BS2: High AC in GnomAdExome4 at 6 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNA6	NM_002235.5	c.644C>T	p.Ser215Phe	missense_variant	1/1	ENST00000280684.4	NP_002226.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNA6	ENST00000280684.4	c.644C>T	p.Ser215Phe	missense_variant	1/1	6	NM_002235.5	ENSP00000280684.3
GALNT8	ENST00000542998.5	c.310-40053C>T		intron_variant		3		ENSP00000440383.1
ENSG00000256988	ENST00000662877.1	n.409+2871G>A		intron_variant
ENSG00000256988	ENST00000664363.1	n.1626+2871G>A		intron_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251140 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135706

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461874 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727244

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: 0.0000464

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 10, 2023

The c.644C>T (p.S215F) alteration is located in exon 1 (coding exon 1) of the KCNA6 gene. This alteration results from a C to T substitution at nucleotide position 644, causing the serine (S) at amino acid position 215 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.092
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.070
CADD	Benign	17
DANN	Benign	0.78
DEOGEN2	Uncertain	0.53	.;D
Eigen	Benign	-0.46
Eigen_PC	Benign	-0.48
FATHMM_MKL	Benign	0.42	N
LIST_S2	Benign	0.53	.;T
M_CAP	Uncertain	0.16	D
MetaRNN	Benign	0.15	T;T
MetaSVM	Uncertain	0.11	D
MutationAssessor	Benign	0.81	.;L
PrimateAI	Benign	0.36	T
PROVEAN	Benign	0.54	N;N
REVEL	Uncertain	0.37
Sift	Benign	0.48	T;T
Sift4G	Benign	0.12	T;T
Polyphen		0.51	.;P
Vest4		0.17
MutPred		0.52		Gain of catalytic residue at S212 (P = 5e-04);Gain of catalytic residue at S212 (P = 5e-04);
MVP		0.55
MPC		1.2
ClinPred		0.14	T
GERP RS		4.5
Varity_R		0.056
gMVP		0.75

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: rs763610784; hg19: chr12-4919851;