rs62516147

chr12-102844335-C-Achr12-102844335-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PVS1_Moderate PM2 PP3_Strong PP5_Very_Strong

The NM_000277.3(PAH):c.1065+1G>T variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: PAH NM_000277.3 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic reviewed by expert panel P:6
• Conservation: PhyloP100: 7.91

Genes affected

PAH (HGNC:8582): (phenylalanine hydroxylase) This gene encodes a member of the biopterin-dependent aromatic amino acid hydroxylase protein family. The encoded phenylalanine hydroxylase enzyme hydroxylates phenylalanine to tyrosine and is the rate-limiting step in phenylalanine catabolism. Deficiency of this enzyme activity results in the autosomal recessive disorder phenylketonuria. [provided by RefSeq, Aug 2017]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.06990434 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.3, offset of 39, new splice context is: gtgGTgggt. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 12-102844335-C-A is Pathogenic according to our data. Variant chr12-102844335-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 203872.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr12-102844335-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PAH	NM_000277.3	c.1065+1G>T		splice_donor_variant		ENST00000553106.6
PAH	NM_001354304.2	c.1065+1G>T		splice_donor_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PAH	ENST00000553106.6	c.1065+1G>T		splice_donor_variant		1	NM_000277.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1448756 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 721742

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:6

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Oct 14, 2022	- -
Likely pathogenic, reviewed by expert panel	curation	ClinGen PAH Variant Curation Expert Panel	Oct 19, 2020	This c.1065+1G>T variant in PAH was reported in 1 patient with moderate PKU (PMID: 18299955) detected with the pathogenic variant p.Leu48Ser. A defect in BH4 metabolism was not excluded. This variant is absent from population databases. This variant in the +1 splice donor site results in exon skipping. The variant does not disrupt the reading frame, but the altered region is critical to protein function. In summary, this variant meets criteria to be classified as likely pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PVS1_strong, PM2, PP4, PM3_supporting. -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	Sep 01, 2022	The variant is not observed in the gnomAD v2.1.1 dataset. Canonical splice site is predicted to alter splicing and result in a loss or disruption of normal protein function. Multiple pathogenic loss-of-function variants are reported downstream of the variant. The variant has been reported multiple times as an established pathogenic variant (ClinVar ID: VCV000203872). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Feb 01, 2022	Variant summary: PAH c.1065+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 a 5 splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 251134 control chromosomes (gnomAD). c.1065+1G>T has been reported in the literature in individuals affected with Phenylalanine Hydroxylase Deficiency (Phenylketonuria and Hyperphenylalaninemia) (Bercovich_2008, Li_2015, Li_2018, Wang_2018, Hillert_2020). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two ClinVar submitters have assessed this variant since 2014: one classified the variant as likely pathogenic and the other as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jun 23, 2023	Disruption of this splice site has been observed in individual(s) with hyperphenylalaninemia (PMID: 18299955). 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: 203872). This variant is also known as IVS10+1G>T. This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 10 of the PAH 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 PAH are known to be pathogenic (PMID: 1301187, 9634518). -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Nov 01, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.44
Cadd	Pathogenic	34
Dann	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.60		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.60		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: rs62516147; hg19: chr12-103238113;