chr9-105604381-G-C

Variant names:

• chr9-105604381-G-C
• rs119463994
• NM_001079802.2:c.536G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_001079802.2(FKTN):​c.536G>C​(p.Arg179Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,718 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). Synonymous variant affecting the same amino acid position (i.e. R179R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: FKTN NM_001079802.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:1
• Conservation: PhyloP100: 8.44
• Publications: 8 publications found

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 Gene-Disease associations (from GenCC):

• autosomal recessive limb-girdle muscular dystrophy type 2M

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 4

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet, G2P
• myopathy caused by variation in FKTN

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• congenital muscular dystrophy without intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• muscle-eye-brain disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• muscular dystrophy-dystroglycanopathy, type A

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• dilated cardiomyopathy 1X

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 17 uncertain in NM_001079802.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 9-105604381-G-C is Pathogenic according to our data. Variant chr9-105604381-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 3210.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001079802.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FKTN	NM_001079802.2	MANE Select	c.536G>C	p.Arg179Thr	missense	Exon 6 of 11	NP_001073270.1
	FKTN	NM_001351496.2		c.536G>C	p.Arg179Thr	missense	Exon 7 of 12	NP_001338425.1
	FKTN	NM_006731.2		c.536G>C	p.Arg179Thr	missense	Exon 5 of 10	NP_006722.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FKTN	ENST00000357998.10	TSL:5 MANE Select	c.536G>C	p.Arg179Thr	missense	Exon 6 of 11	ENSP00000350687.6
	FKTN	ENST00000223528.6	TSL:1	c.536G>C	p.Arg179Thr	missense	Exon 5 of 10	ENSP00000223528.2
	FKTN	ENST00000602526.1	TSL:1	n.*574G>C		non_coding_transcript_exon	Exon 6 of 11	ENSP00000473347.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461718 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727168

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111856

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
2	-	-	Dilated cardiomyopathy 1X (2)
1	-	-	not provided (1)
-	1	-	Walker-Warburg congenital muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.69	D
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D
M_CAP	Uncertain	0.23	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.3	M
PhyloP100		8.4
PrimateAI	Uncertain	0.64	T
PROVEAN	Uncertain	-3.4	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.016	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.92		Gain of glycosylation at S180 (P = 0.0902)
MVP		0.92
MPC		0.55
ClinPred		0.99	D
GERP RS		5.4
Varity_R		0.77
gMVP		0.97
Mutation Taster		=1/99	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs119463994; hg19: chr9-108366662;