rs119463995

Positions:

• chr9-105601319-G-A
• chr9-105601319-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_001079802.2(FKTN):​c.340G>A​(p.Ala114Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,454,890 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: FKTN NM_001079802.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 8.09

Genes affected

FKTN (HGNC:3622): (fukutin) The protein encoded by this gene is a putative transmembrane protein that is localized to the cis-Golgi compartment, where it may be involved in the glycosylation of alpha-dystroglycan in skeletal muscle. The encoded protein is thought to be a glycosyltransferase and could play a role in brain development. Defects in this gene are a cause of Fukuyama-type congenital muscular dystrophy (FCMD), Walker-Warburg syndrome (WWS), limb-girdle muscular dystrophy type 2M (LGMD2M), and dilated cardiomyopathy type 1X (CMD1X). Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Nov 2010]

FKTN (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.942
• PP5: Variant 9-105601319-G-A is Pathogenic according to our data. Variant chr9-105601319-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 3213.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=1}. Variant chr9-105601319-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FKTN	NM_001079802.2	c.340G>A	p.Ala114Thr	missense_variant	5/11	ENST00000357998.10	NP_001073270.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FKTN	ENST00000357998.10	c.340G>A	p.Ala114Thr	missense_variant	5/11	5	NM_001079802.2	ENSP00000350687.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1454890 Hom.: 0 Cov.: 29 AF XY: 0.00000276 AC XY: 2 AN XY: 724110

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: 0.00000181

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2M Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

May 01, 2009

- -

Walker-Warburg congenital muscular dystrophy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 01, 2023

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on FKTN protein function. ClinVar contains an entry for this variant (Variation ID: 3213). This missense change has been observed in individual(s) with FKTN-related conditions (PMID: 17878207, 19342235). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 114 of the FKTN protein (p.Ala114Thr). -

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 4 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Counsyl

Jan 09, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.51
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.38	T;T;.;.
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.87	.;D;.;D
M_CAP	Uncertain	0.14	D
MetaRNN	Pathogenic	0.94	D;D;D;D
MetaSVM	Uncertain	0.78	D
MutationAssessor	Uncertain	2.2	M;M;M;M
PrimateAI	Uncertain	0.57	T
PROVEAN	Benign	-1.2	.;N;D;N
REVEL	Pathogenic	0.83
Sift	Uncertain	0.0090	.;D;D;D
Sift4G	Benign	0.094	T;T;T;T
Polyphen		0.99	D;D;.;.
Vest4		0.66
MutPred		0.81		Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);Loss of helix (P = 0.0237);
MVP		0.94
MPC		0.31
ClinPred		0.96	D
GERP RS		5.8
Varity_R		0.18
gMVP		0.88

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: rs119463995; hg19: chr9-108363600;