12-39294488-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_001173464.2(KIF21A):c.4961G>T(p.Arg1654Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,508 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1654H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: KIF21A NM_001173464.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.679

Genes affected

KIF21A (HGNC:19349): (kinesin family member 21A) This gene encodes a member of the KIF4 subfamily of kinesin-like motor proteins. The encoded protein is characterized by an N-terminal motor domain a coiled-coil stalk domain and a C-terminal WD-40 repeat domain. This protein may be involved in microtubule dependent transport. Mutations in this gene are the cause of congenital fibrosis of extraocular muscles-1. Alternate splicing results in multiple transcript variants.[provided by RefSeq, Mar 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, KIF21A
• BP4: Computational evidence support a benign effect (MetaRNN=0.18775868).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KIF21A	NM_001173464.2	c.4961G>T	p.Arg1654Leu	missense_variant	38/38	ENST00000361418.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KIF21A	ENST00000361418.10	c.4961G>T	p.Arg1654Leu	missense_variant	38/38	1	NM_001173464.2	A1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249900 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135096

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: 0.00000890

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461508 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727050

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 Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital fibrosis of extraocular muscles type 1 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
AlphaMissense	Benign	0.21
BayesDel_addAF	Uncertain	0.013	T
BayesDel_noAF	Benign	-0.22
Cadd	Benign	21
Dann	Uncertain	0.99
DEOGEN2	Benign	0.030	T;.;T;.;T;.
Eigen	Benign	-0.13
Eigen_PC	Benign	-0.065
FATHMM_MKL	Benign	0.65	D
LIST_S2	Uncertain	0.97	D;D;D;D;D;D
M_CAP	Benign	0.043	D
MetaRNN	Benign	0.19	T;T;T;T;T;T
MetaSVM	Benign	-0.72	T
MutationTaster	Benign	0.97	N;N;N;N;N
PrimateAI	Benign	0.25	T
Polyphen		0.11, 0.12	.;B;.;.;B;.
Vest4		0.35, 0.53, 0.58, 0.65
MutPred		0.34		.;.;.;.;Loss of methylation at K1652 (P = 0.046);.;
MVP		0.71
MPC		0.40
ClinPred		0.92	D
GERP RS		3.3
Varity_R		0.13
gMVP		0.64

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: rs373406994; hg19: chr12-39688290;