NM_001079802.2:c.166C>G

Variant names:

• chr9-105601145-C-G
• rs41277797
• NM_001079802.2:c.166C>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001079802.2(FKTN):​c.166C>G​(p.Arg56Gly) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000071 in 1,407,762 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R56H) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: FKTN NM_001079802.2 missense, splice_region
• Scores: Splicing: ADA: 0.8564
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.54
• Publications: 0 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: G2P, Orphanet, Labcorp Genetics (formerly Invitae)
• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 4

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
• 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: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FKTN	NM_001079802.2	MANE Select	c.166C>G	p.Arg56Gly	missense splice_region	Exon 5 of 11	NP_001073270.1	O75072-1
	FKTN	NM_001351496.2		c.166C>G	p.Arg56Gly	missense splice_region	Exon 6 of 12	NP_001338425.1	O75072-1
	FKTN	NM_006731.2		c.166C>G	p.Arg56Gly	missense splice_region	Exon 4 of 10	NP_006722.2	O75072-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FKTN	ENST00000357998.10	TSL:5 MANE Select	c.166C>G	p.Arg56Gly	missense splice_region	Exon 5 of 11	ENSP00000350687.6	O75072-1
	FKTN	ENST00000223528.6	TSL:1	c.166C>G	p.Arg56Gly	missense splice_region	Exon 4 of 10	ENSP00000223528.2	O75072-1
	FKTN	ENST00000602526.1	TSL:1	n.*86C>G		splice_region non_coding_transcript_exon	Exon 4 of 11	ENSP00000473347.1	R4GMU0

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.10e-7 AC: 1 AN: 1407762 Hom.: 0 Cov.: 26 AF XY: 0.00000142 AC XY: 1 AN XY: 703324

African (AFR) AF: 0.00 AC: 0 AN: 32480

American (AMR) AF: 0.00 AC: 0 AN: 44338

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25688

East Asian (EAS) AF: 0.00 AC: 0 AN: 39346

South Asian (SAS) AF: 0.0000118 AC: 1 AN: 84736

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52898

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1064518

Other (OTH) AF: 0.00 AC: 0 AN: 58464

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.030
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.25	T
Eigen	Uncertain	0.34
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.89	D
M_CAP	Benign	0.080	D
MetaRNN	Uncertain	0.45	T
MetaSVM	Uncertain	0.51	D
MutationAssessor	Benign	1.9	L
PhyloP100		2.5
PrimateAI	Benign	0.23	T
PROVEAN	Benign	-1.8	N
REVEL	Uncertain	0.45
Sift	Benign	0.12	T
Sift4G	Benign	0.36	T
Polyphen		0.47	P
Vest4		0.50
MutPred		0.37		Loss of MoRF binding (P = 0.0043)
MVP		0.90
MPC		0.12
ClinPred		0.85	D
GERP RS		5.7
Varity_R		0.18
gMVP		0.55
Mutation Taster		=71/29	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.86
dbscSNV1_RF	Benign	0.54
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: rs41277797; hg19: chr9-108363426;