19-46755463-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_024301.5(FKRP):c.13C>T(p.Arg5Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000687 in 1,454,862 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. R5R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: FKRP NM_024301.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 0.831

Genes affected

FKRP (HGNC:17997): (fukutin related protein) This gene encodes a protein which is targeted to the medial Golgi apparatus and is necessary for posttranslational modification of dystroglycan. Mutations in this gene have been associated with congenital muscular dystrophy, cognitive disability, and cerebellar cysts. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined. [provided by RefSeq, Oct 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FKRP	NM_024301.5	c.13C>T	p.Arg5Cys	missense_variant	4/4	ENST00000318584.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FKRP	ENST00000318584.10	c.13C>T	p.Arg5Cys	missense_variant	4/4	1	NM_024301.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.87e-7 AC: 1 AN: 1454862 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 723890

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2I Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Jan 13, 2021

- -

Walker-Warburg congenital muscular dystrophy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 28, 2016

This sequence change replaces arginine with cysteine at codon 5 of the FKRP protein (p.Arg5Cys). The arginine residue is moderately conserved and there is a large physicochemical difference between arginine and cysteine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with an FKRP-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.010
Cadd	Benign	23
Dann	Uncertain	1.0
Eigen	Uncertain	0.33
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Benign	0.72	D
LIST_S2	Uncertain	0.87	D;.;D;T;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.65	D
MetaRNN	Uncertain	0.47	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.76	T
Sift4G	Benign	0.080	T;T;D;D;D;D;T;D;D;D;D;D;D;D;D;D;D
Polyphen		1.0	.;D;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.
Vest4		0.43, 0.48
MutPred		0.39		Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);
MVP		0.98
MPC		1.6
ClinPred		0.90	D
GERP RS		4.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.6
Varity_R		0.11
gMVP		0.59

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: rs1060502108; hg19: chr19-47258720;