rs62642935

chr12-102846938-G-Achr12-102846938-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000277.3(PAH):c.926C>T(p.Ala309Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000229 in 1,613,432 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A309T) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000024 (0 hom.)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:8 O:1
• Conservation: PhyloP100: 9.60

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 18 ACMG points.

• PM1: In a hotspot region, there are 11 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000277.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr12-102846939-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1327567.Status of the report is reviewed_by_expert_panel, 3 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.959
• PP5: Variant 12-102846938-G-A is Pathogenic according to our data. Variant chr12-102846938-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 92753.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr12-102846938-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PAH	NM_000277.3	c.926C>T	p.Ala309Val	missense_variant	9/13	ENST00000553106.6
PAH	NM_001354304.2	c.926C>T	p.Ala309Val	missense_variant	10/14

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PAH	ENST00000553106.6	c.926C>T	p.Ala309Val	missense_variant	9/13	1	NM_000277.3	P1

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 152080 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000159 AC: 4 AN: 251284 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135794

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000240 AC: 35 AN: 1461352 Hom.: 0 Cov.: 30 AF XY: 0.0000261 AC XY: 19 AN XY: 727014

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: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000297

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 152080 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74282

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000380 Hom.: 0

Bravo AF: 0.0000113

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:6

Pathogenic, reviewed by expert panel	curation	ClinGen PAH Variant Curation Expert Panel	Aug 10, 2018	PAH-specific ACMG/AMP criteria applied: PM2: Low frequency. 1.0e-5; PP3: All databases agree on damaging effect. REVEL=0.921; PS3: Enzyme activity = 30% (Ho, 2008) (PMID:18590700); PM3: Single patient with classic PKU, c.842C>T (pathogenic in ClinVar) / c.926C>T (PMID:26666653); PP4: Single patient with classic PKU (>1200umol/L), BH4 defect not excluded (PMID:26666653). In summary this variant meets criteria to be classified as pathogenic for phenylketonuria in an autosomal recessive manner based on the ACMG/AMP criteria applied as specified by the PAH Expert Panel: (PM2, PP3, PS3, PM3, PP4). -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Oct 09, 2023	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Likely pathogenic, no assertion criteria provided	clinical testing	Counsyl	Oct 20, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 01, 2023	This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 309 of the PAH protein (p.Ala309Val). This variant is present in population databases (rs62642935, gnomAD 0.003%). This missense change has been observed in individual(s) with PKU (PMID: 12655546, 21871829, 26666653, 27121329). ClinVar contains an entry for this variant (Variation ID: 92753). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt PAH protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects PAH function (PMID: 12655546, 15459954, 16504182). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jul 19, 2021	Variant summary: PAH c.926C>T (p.Ala309Val) results in a non-conservative amino acid change located in the Aromatic amino acid hydroxylase, C-terminal domain (IPR019774) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.6e-05 in 251284 control chromosomes. c.926C>T has been reported in the literature in multiple individuals affected with Phenylalanine Hydroxylase Deficiency (Phenylketonuria) (example, Hennermann_2000, Ley_2003, Dobrowolski_2007, Rivera_2011, Aldamiz-Echevarria_2016). These data indicate that the variant is very likely to be associated with disease. Multiple publications report experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in reduced enzyme activity, folding defect causing reduced stability and accelarated degradation (example, Ley_2003, Aldamiz-Echevarria_2016). Multiple clinical diagnostic laboratories and an expert panel (ClinGen PAH Variant Curation Expert Panel) have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All submitters classified the variant as pathogenic (n=4)/likely pathogenic (n=1). Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided Pathogenic:2 Other:1

not provided, no classification provided	literature only	DeBelle Laboratory for Biochemical Genetics, MUHC/MCH RESEARCH INSTITUTE	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Oct 05, 2023	Not observed at a significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Classified as responsive to tetrahydrobiopterin (BH4) therapy (Zurflh et al., 2008; Aldmiz- Echevarra et al., 2016); This variant is associated with the following publications: (PMID: 23559577, 16051511, 8830172, 16091306, 10679941, 15459954, 8533759, 25087612, 21953985, 8268925, 16504182, 15464430, 10234516, 26990548, 32668217, 31589614, 32778825, 12655546, 17935162, 33465300, 30037505, 27121329) -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Aug 07, 2012	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.49
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.54
Cadd	Pathogenic	30
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.75	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Uncertain	2.9	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.67	T
PROVEAN	Uncertain	-3.4	D;D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.015	D;D
Sift4G	Uncertain	0.021	D;D
Polyphen		1.0	D;.
Vest4		0.96
MVP		0.98
MPC		0.20
ClinPred		0.94	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.86
gMVP		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs62642935; hg19: chr12-103240716; COSMIC: COSV100187930;