19-46746094-A-T

Variant names:

• chr19-46746094-A-T
• rs2054592600
• NM_013403.3:c.282+55T>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_024301.5(FKRP):​c.-253+4A>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000364 in 1,098,664 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 28)
  • Exomes 𝑓: 0.0000036 (0 hom.)
• Consequence: FKRP NM_024301.5 splice_region, intron
• Scores: Splicing: ADA: 0.9937
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.159
• Publications: 0 publications found

Genes affected

STRN4 (HGNC:15721): (striatin 4) Enables armadillo repeat domain binding activity and protein phosphatase 2A binding activity. Part of FAR/SIN/STRIPAK complex. [provided by Alliance of Genome Resources, Apr 2022]

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: Laboratory for Molecular Medicine, Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics
• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A5

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

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Myriad Women’s Health, Labcorp Genetics (formerly Invitae)
• 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: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
STRN4	NM_013403.3	c.282+55T>A		intron_variant	Intron 1 of 17	ENST00000263280.11	NP_037535.2
FKRP	NM_024301.5	c.-253+4A>T		splice_region_variant, intron_variant	Intron 1 of 3	ENST00000318584.10	NP_077277.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
STRN4	ENST00000263280.11	c.282+55T>A		intron_variant	Intron 1 of 17	1	NM_013403.3	ENSP00000263280.4
FKRP	ENST00000318584.10	c.-253+4A>T		splice_region_variant, intron_variant	Intron 1 of 3	1	NM_024301.5	ENSP00000326570.4

Frequencies

GnomAD3 genomes Cov.: 28

GnomAD4 exome AF: 0.00000364 AC: 4 AN: 1098664 Hom.: 0 Cov.: 33 AF XY: 0.00000186 AC XY: 1 AN XY: 536832

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 19800

American (AMR) AF: 0.00 AC: 0 AN: 9284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 12914

East Asian (EAS) AF: 0.00 AC: 0 AN: 16466

South Asian (SAS) AF: 0.00 AC: 0 AN: 56476

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 19656

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 3420

European-Non Finnish (NFE) AF: 0.00000435 AC: 4 AN: 919684

Other (OTH) AF: 0.00 AC: 0 AN: 40964

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 28

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.68
CADD	Benign	18
DANN	Benign	0.89
PhyloP100		0.16
PromoterAI		0.15	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.4

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Pathogenic	0.73
SpliceAI score (max)		0.39		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.39		Position offset: -4

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs2054592600; hg19: chr19-47249351;