rs752243337

Variant names:

• chr19-46756868-T-G
• rs752243337
• NM_024301.5:c.1418T>G

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PS3 PM1 PM2 PP2 PP3_Strong PP5

The NM_024301.5(FKRP):​c.1418T>G​(p.Phe473Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,458,966 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). ClinVar reports functional evidence for this variant: "SCV006080919: While phase of these variants was not reported, functional studies in induced pluripotent stem cells generated from this affected individual demonstrated impaired alpha-DG functional glycosylation (Ortiz-Cordero et al., 2021).". Synonymous variant affecting the same amino acid position (i.e. F473F) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: FKRP NM_024301.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 7.75
• Publications: 2 publications found

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]

FKRP Gene-Disease associations (from GenCC):

• autosomal recessive limb-girdle muscular dystrophy type 2I

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, Ambry Genetics
• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A5

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Genomics England PanelApp, Ambry Genetics
• muscular dystrophy-dystroglycanopathy type B5

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Myriad Women’s Health
• myopathy caused by variation in FKRP

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• congenital muscular dystrophy with cerebellar involvement

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• congenital muscular dystrophy with intellectual disability

  Inheritance: AR 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

ACMG classification

Our verdict: Pathogenic. The variant received 14 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV006080919: While phase of these variants was not reported, functional studies in induced pluripotent stem cells generated from this affected individual demonstrated impaired alpha-DG functional glycosylation (Ortiz-Cordero et al., 2021).
• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 16 uncertain in NM_024301.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 46 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 1.8498 (below the threshold of 3.09). Trascript score misZ: -2.4986 (below the threshold of 3.09). GenCC associations: The gene is linked to muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A5, muscle-eye-brain disease, congenital muscular dystrophy with cerebellar involvement, muscular dystrophy-dystroglycanopathy, type A, autosomal recessive limb-girdle muscular dystrophy type 2I, muscular dystrophy-dystroglycanopathy type B5, congenital muscular dystrophy without intellectual disability, myopathy caused by variation in FKRP, congenital muscular dystrophy with intellectual disability.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.963
• PP5: Variant 19-46756868-T-G is Pathogenic according to our data. Variant chr19-46756868-T-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 550064.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_024301.5. 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
	FKRP	NM_024301.5	MANE Select	c.1418T>G	p.Phe473Cys	missense	Exon 4 of 4	NP_077277.1	Q9H9S5
	FKRP	NM_001039885.3		c.1418T>G	p.Phe473Cys	missense	Exon 4 of 4	NP_001034974.1	Q9H9S5

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FKRP	ENST00000318584.10	TSL:1 MANE Select	c.1418T>G	p.Phe473Cys	missense	Exon 4 of 4	ENSP00000326570.4	Q9H9S5
	FKRP	ENST00000391909.7	TSL:2	c.1418T>G	p.Phe473Cys	missense	Exon 4 of 4	ENSP00000375776.2	Q9H9S5
	FKRP	ENST00000908841.1		c.1418T>G	p.Phe473Cys	missense	Exon 3 of 3	ENSP00000578900.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000825 AC: 2 AN: 242340 AF XY: 0.00000755

Gnomad AFR exome AF: 0.000137

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1458966 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 725580

African (AFR) AF: 0.0000897 AC: 3 AN: 33432

American (AMR) AF: 0.00 AC: 0 AN: 44428

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26014

East Asian (EAS) AF: 0.00 AC: 0 AN: 39664

South Asian (SAS) AF: 0.00 AC: 0 AN: 85846

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52384

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5742

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111168

Other (OTH) AF: 0.00 AC: 0 AN: 60288

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ExAC AF: 0.00000825 AC: 1

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	-	Autosomal recessive limb-girdle muscular dystrophy type 2I (1)
1	-	-	Autosomal recessive limb-girdle muscular dystrophy type 2I;C1847759:Muscular dystrophy-dystroglycanopathy type B5;C3150413:Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A5 (1)
-	1	-	Walker-Warburg congenital muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	30
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.86	D
Eigen	Uncertain	0.65
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.88	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		7.7
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-5.1	D
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.76		Gain of methylation at K472 (P = 0.0333)
MVP		0.98
MPC		2.0
ClinPred		0.99	D
GERP RS		5.2
Varity_R		0.81
gMVP		0.91
Mutation Taster		=1/99	disease causing

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: rs752243337; hg19: chr19-47260125;