12-102855224-G-T

Variant names:

• chr12-102855224-G-T
• rs62517201
• NM_000277.3:c.618C>A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1 PP4 PM2_Supporting PM3_Strong

This summary comes from the ClinGen Evidence Repository: The c.618C>A (p.Tyr206Ter) is a nonsense variant predicted to cause a premature stop codon in biologically relevant exon 6/13 leading to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism. It has been detected in 4 patients with classic PKU with known pathogenic variants: c.611A>G (PMID:16256386); p.Arg241Cys (PMID:25456745); and c.1197A>T p.Val399Val (PMID:30050108). This variant has extremely low frequency in gnomAD (MAF=0.00005). In summary, this variant meets criteria to be classified as Pathogenic for PAH deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen PAH VCEP: PM2_supporting, PM3_strong, PP4, PVS1. LINK:https://erepo.genome.network/evrepo/ui/classification/CA6748887/MONDO:0009861/006

• Frequency: Genomes: not found (cov: 33)
• Consequence: PAH NM_000277.3 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:6
• Conservation: PhyloP100: 5.94

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 14 ACMG points.

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PAH	NM_000277.3	c.618C>A	p.Tyr206*	stop_gained	Exon 6 of 13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.618C>A	p.Tyr206*	stop_gained	Exon 7 of 14		NP_001341233.1
PAH	XM_017019370.2	c.618C>A	p.Tyr206*	stop_gained	Exon 6 of 7		XP_016874859.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6	c.618C>A	p.Tyr206*	stop_gained	Exon 6 of 13	1	NM_000277.3	ENSP00000448059.1
PAH	ENST00000549111.5	n.714C>A		non_coding_transcript_exon_variant	Exon 6 of 6	1
PAH	ENST00000307000.7	c.603C>A	p.Tyr201*	stop_gained	Exon 7 of 14	5		ENSP00000303500.2
PAH	ENST00000551988.5	n.*55C>A		downstream_gene_variant		3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251330 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135818

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:6

Nov 06, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 13, 2023

ClinGen PAH Variant Curation Expert Panel

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The c.618C>A (p.Tyr206Ter) is a nonsense variant predicted to cause a premature stop codon in biologically relevant exon 6/13 leading to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism. It has been detected in 4 patients with classic PKU with known pathogenic variants: c.611A>G (PMID: 16256386); p.Arg241Cys (PMID:25456745); and c.1197A>T p.Val399Val (PMID: 30050108). This variant has extremely low frequency in gnomAD (MAF=0.00005). In summary, this variant meets criteria to be classified as Pathogenic for PAH deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen PAH VCEP: PM2_supporting, PM3_strong, PP4, PVS1. -

Oct 22, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Tyr206*) in the PAH gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PAH are known to be pathogenic (PMID: 1301187, 9634518). This variant is present in population databases (rs62517201, gnomAD 0.006%). This premature translational stop signal has been observed in individual(s) with phenylketonuria (PMID: 16256386, 24130151, 27121329). ClinVar contains an entry for this variant (Variation ID: 556660). For these reasons, this variant has been classified as Pathogenic. -

Feb 13, 2018

Counsyl

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 16, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Sep 08, 2017

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: The PAH c.618C>A (p.Tyr206X) variant results in a premature termination codon, predicted to cause a truncated or absent PAH protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (e.g. c.727C>T, p.Arg243X; c.1055delG, p.Gly352fsX48; c.1089delG, p.Lys363fsX37). One in silico tool predicts a damaging outcome for this variant. One functional study confirmed that the variant leads to a nonsense mutation that caused significant reduction in mutant transcript levels possibly through activation of nonsense mediated decay (Bashyam 2014). This variant was found in 1/121330 control chromosomes at a frequency of 0.00082%, which does not exceed the estimated maximal expected allele frequency of a pathogenic PAH variant (0.79057%). The variant was reported in the literature in multiple patients with PKU (Song 2006, Bashyam 2014, Li 2015, Acosta 2001). Taken together, this variant is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	40
DANN	Uncertain	1.0
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	0.98	D
Vest4		0.93
GERP RS		5.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs62517201; hg19: chr12-103249002;