rs374203636

chr9-105575115-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_001079802.2(FKTN):c.83A>G(p.Tyr28Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000346 in 1,446,630 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000035 (0 hom.)
• Consequence: FKTN NM_001079802.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.38

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a transmembrane_region Helical; Signal-anchor for type II membrane protein (size 20) in uniprot entity FKTN_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_001079802.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.864

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FKTN	NM_001079802.2	c.83A>G	p.Tyr28Cys	missense_variant	3/11	ENST00000357998.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FKTN	ENST00000357998.10	c.83A>G	p.Tyr28Cys	missense_variant	3/11	5	NM_001079802.2	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251298 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135824

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000346 AC: 5 AN: 1446630 Hom.: 0 Cov.: 26 AF XY: 0.00000555 AC XY: 4 AN XY: 720778

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: 0.00000455

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.0000113

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Walker-Warburg congenital muscular dystrophy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 18, 2022

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 28 of the FKTN protein (p.Tyr28Cys). This variant is present in population databases (rs374203636, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with FKTN-related conditions. ClinVar contains an entry for this variant (Variation ID: 528822). 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"). 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	Benign	0.16
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Pathogenic	0.14
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Benign	0.35	T;T;.;.
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Uncertain	0.80	D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.86	D;D;D;D
MetaSVM	Uncertain	0.68	D
MutationAssessor	Uncertain	2.2	M;M;M;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.63	T
Sift4G	Uncertain	0.019	D;D;D;D
Polyphen		1.0	D;D;.;.
Vest4		0.80
MVP		0.93
MPC		0.39
ClinPred		0.89	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.20
gMVP		0.79

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: rs374203636; hg19: chr9-108337396;