15-80168263-G-T
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong
The NM_000137.4(FAH):c.554-1G>T variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000199 in 1,604,106 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 Pathogenic (★★).
Frequency
Consequence
NM_000137.4 splice_acceptor, intron
Scores
Clinical Significance
Conservation
Publications
- tyrosinemia type IInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Laboratory for Molecular Medicine, G2P, Orphanet, Ambry Genetics, ClinGen
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ACMG classification
Our verdict: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| FAH | NM_000137.4 | c.554-1G>T | splice_acceptor_variant, intron_variant | Intron 6 of 13 | ENST00000561421.6 | NP_000128.1 | ||
| FAH | NM_001374377.1 | c.554-1G>T | splice_acceptor_variant, intron_variant | Intron 7 of 14 | NP_001361306.1 | |||
| FAH | NM_001374380.1 | c.554-1G>T | splice_acceptor_variant, intron_variant | Intron 7 of 14 | NP_001361309.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| FAH | ENST00000561421.6 | c.554-1G>T | splice_acceptor_variant, intron_variant | Intron 6 of 13 | 1 | NM_000137.4 | ENSP00000453347.2 |
Frequencies
GnomAD3 genomes AF: 0.000106 AC: 16AN: 150484Hom.: 0 Cov.: 31 show subpopulations
GnomAD2 exomes AF: 0.000152 AC: 38AN: 249864 AF XY: 0.000148 show subpopulations
GnomAD4 exome AF: 0.000209 AC: 304AN: 1453514Hom.: 0 Cov.: 36 AF XY: 0.000220 AC XY: 159AN XY: 723500 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000106 AC: 16AN: 150592Hom.: 0 Cov.: 31 AF XY: 0.0000818 AC XY: 6AN XY: 73360 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Tyrosinemia type I Pathogenic:13Other:1
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Southern European-specific pathogenic variant resulting from founder effect or genetic drift [Angileri et al 2015]. -
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Criteria applied: PVS1,PM3_VSTR,PM2_SUP,PP4 -
This sequence change affects an acceptor splice site in intron 6 of the FAH gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or altered protein product. This variant is present in population databases (rs80338895, gnomAD 0.03%). Disruption of this splice site has been observed in individual(s) with tyrosinemia type 1 (PMID: 8829657, 11476670, 12203990). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is also known as IVS6-1. ClinVar contains an entry for this variant (Variation ID: 11874). Studies have shown that disruption of this splice site results in skipping of exon 8, and produces a non-functional protein and/or introduces a premature termination codon (PMID: 8557261, 11476670). For these reasons, this variant has been classified as Pathogenic. -
ACMG classification criteria: PVS1 very strong, PS4 strong, PM2 moderate, PM3 very strong -
NM_000137.2(FAH):c.554-1G>T(aka IVS6-1G>T) is classified as pathogenic in the context of tyrosinemia type I. Sources cited for classification include the following: PMID 8557261, 23348723, 21752152, 12203990, and 9633815. Classification of NM_000137.2(FAH):c.554-1G>T(aka IVS6-1G>T) is based on the following criteria: The variant is located at a canonical splice site, is expected to disrupt gene function and is reported in individuals with the relevant phenotype. Please note: this variant was assessed in the context of healthy population screening. -
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Variant summary: The FAH c.554-1G>T variant involves the alteration of a conserved intronic nucleotide located in the canonical splice site at the junction of intron6/exon7 border. Mutation taster predicts a damaging outcome for this variant along with 5/5 splice prediction tools predicting the variant to eliminate the splice acceptor site. This variant was found in 13/121368 control chromosomes at a frequency of 0.0001071, which does not exceed the estimated maximal expected allele frequency of a pathogenic FAH variant (0.0025). This variant has been reported in several Tyrosemia type 1 patients either in homozygosity or compound heterozygosity with other potentially pathogenic FAH variant indicating pathogenicity of this variant. RT-PCR products amplified from total RNA extracted from cultured fibroblasts of a patient homozygous for IVS6-1G->T showed aberrant splicing pattern further supporting its deleterious impact. In addition, another variant affecting the same position, c.554-1G>C is reported in HGMD as a disease causing mutation. Moreover, multiple clinical diagnostic laboratories/reputable databases classified this variant as pathogenic. Considering all evidence, the variant is classified as pathogenic. -
The FAH c.554-1G>T variant, also known IVS6-1G>T, occurs in a canonical splice site (acceptor) and is therefore predicted to disrupt or distort the normal gene product. The c.554-1G>T variant is a well described common FAH pathogenic variant, accounting for over 16% of tyrosinemia disease-associated alleles worldwide (Sniderman King et al. 2006; Angileri et al. 2015). Across a selection of the available literature, the c.554-1G>T variant has been reported in at least 71 patients including in 48 in a homozygous state, in 16 in a compound heterozygous state, and in seven in a heterozygous state in whom a second variant has not been detected (Rootwelt et al. 1996; Timmers et al. 1996; Bergman et al. 1998; Dreumont et al. 2001; Arranz et al. 2002; la Marca et al. 2011; Dursun et al. 2011; Laszlo et al. 2013; van Vliet et al. 2015; Mayorandan et al. 2014). The variant was absent from 270 control chromosomes but is reported at a frequency of 0.00035 in the European American population of the Exome Sequencing Project. Functional studies have shown that the variant results in an absence of FAH protein, undetectable FAH activity in patient liver cells and fibroblasts, and a complex pattern of aberrant splicing (Bergman et al. 1998; Arranz et al. 2002; Angileri et al. 2015). Based on the collective evidence and the potential impact of splice acceptor variants, the c.554-1G>T variant is classified as pathogenic for tyrosinemia. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -
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not provided Pathogenic:5
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Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Also known as IVS6-1 G>T; This variant is associated with the following publications: (PMID: 25087612, 11476670, 23348723, 30414057, 30954369, 29625052, 31980526, 34426522, 31589614, 10073910, 32778825, 22975760, 8557261, 12203990, 8829657, 20301688, 25681080, 8723690) -
PVS1, PM2, PM3 -
FAH: PM3:Very Strong, PVS1, PM2, PP4 -
PM2, PM3, PS4, PVS1 -
FAH-related disorder Pathogenic:1
The FAH c.554-1G>T variant is predicted to disrupt the AG splice acceptor site and interfere with normal splicing. This variant, also referred to in the literature as IVS6-1G>T, has previously been reported to be a common causative variant for tyrosinemia type I (see, for example, Rootwelt et al. 1996. PubMed ID: 8829657; Arranz et al. 2002. PubMed ID: 12203990; Angileri et al. 2015. PubMed ID: 25681080). This variant is reported in 0.037% of alleles in individuals of Latino descent in gnomAD. Variants that disrupt consensus splice acceptor sites in FAH are expected to be pathogenic. This variant is interpreted as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at