rs786204683

Positions:

• chr15-80158171-G-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000137.4(FAH):​c.192+1G>T variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000117 in 1,451,764 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: FAH NM_000137.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 8.76

Genes affected

FAH (HGNC:3579): (fumarylacetoacetate hydrolase) Predicted to enable fumarylacetoacetase activity. Predicted to be involved in L-phenylalanine catabolic process; homogentisate catabolic process; and tyrosine catabolic process. Predicted to act upstream of or within arginine catabolic process. Located in extracellular exosome. Implicated in tyrosinemia type I. [provided by Alliance of Genome Resources, Apr 2022]

FAH (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.08730159 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-80158171-G-T is Pathogenic according to our data. Variant chr15-80158171-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 189085.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FAH	NM_000137.4	c.192+1G>T		splice_donor_variant, intron_variant		ENST00000561421.6	NP_000128.1
FAH	NM_001374377.1	c.192+1G>T		splice_donor_variant, intron_variant			NP_001361306.1
FAH	NM_001374380.1	c.192+1G>T		splice_donor_variant, intron_variant			NP_001361309.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FAH	ENST00000561421.6	c.192+1G>T		splice_donor_variant, intron_variant		1	NM_000137.4	ENSP00000453347.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.0000117 AC: 17 AN: 1451764 Hom.: 0 Cov.: 29 AF XY: 0.00000968 AC XY: 7 AN XY: 722894

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: 0.0000136

Gnomad4 OTH exome AF: 0.0000167

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tyrosinemia type I Pathogenic:5

Likely pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Nov 01, 2021	NM_000137.2(FAH):c.192+1G>T is a canonical splice variant classified as likely pathogenic in the context of tyrosinemia type I. c.192+1G>T has been observed in cases with relevant disease (PMID: 9633815). Functional assessments of this variant are not available in the literature. Internal structural analysis of the variant is supportive of pathogenicity. c.192+1G>T has not been observed in population frequency databases. In summary, NM_000137.2(FAH):c.192+1G>T is a canonical splice variant that has internal structural support for pathogenicity and has been observed more frequently in cases with the relevant disease than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -
Likely pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	May 13, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Feb 24, 2020	Variant summary: FAH c.192+1G>T is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes the canonical 5' splicing donor site. One predict the variant weakens the canonical 5' donor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 251492 control chromosomes. c.192+1G>T has been reported as part of a compound heterozygous genotype in the literature in at-least one individual affected with Tyrosinemia Type 1 (example, Bergman_1998). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. No other clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Mar 22, 2023	For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 189085). Disruption of this splice site has been observed in individual(s) with tyrosinemia type I (PMID: 9633815). This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 2 of the FAH gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in FAH are known to be pathogenic (PMID: 9101289, 9633815). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Uncertain	0.060
CADD	Pathogenic	29
DANN	Uncertain	0.99
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.97	D
GERP RS		4.5

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.92
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.99		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs786204683; hg19: chr15-80450513;