12-102846935-G-A

Variant names:

• chr12-102846935-G-A
• rs62642913
• NM_000277.3:c.929C>T

Variant summary

Our verdict is Pathogenic. The variant received 6 ACMG points: 6P and 0B. PP3 PM3 PM2_Supporting PP4_Moderate

This summary comes from the ClinGen Evidence Repository: The NM_000277.1(PAH):c.929C>T (p.Ser310Phe) variant is a missense variant in exon 9/13 of PAH. The variant has been found to result in <1% of wild-type PAH enzyme activity in a standard cDNA and an Intinc system (PMID:18590700) (PS3_supporting). It has been found in at least 8 PKU patients, including among those whom BH4 deficiency was excluding and in trans with other Pathogenic or Likely Pathogenic alleles (PM3_VeryStrong (4.75 points); PP4_Moderate). It has been found in 2 alleles in a survey of German PKU patients (PMID:12655553); in trans with the c.442-1G>A (Pathogenic in ClinVar and by ClinGen PAH VCEP) variant in a Korean patient with moderate PKU (plasma Phe 600-1200 umol/L) with BH4 deficiency excluded by urinary pterin analysis and dihydropteridine reductase (DHPR) assay (PMID:15503242). It has been found in as a homozygous variant in a Syrian patient with classic PKU (plasma Phe 1262 umol/L) (PMID:23856132). It has been found in two Chinese patients with classic PKU and BH4 deficiency excluded via analysis of urinary pterins and dihydropteridine reductase activity in erythrocytes: one harbored it in trans with the p.R111* variant (Pathogenic in ClinVar and by ClinGen PAH VCEP) and one in trans with the p.Y356* variant (Pathogenic in ClinVar and by ClinGen PAH VCEP) (PMID:30050108). It has been found in a Chinese patient with mild hyperphenylalanemia (plasma Phe 120-360 umol/L) in trans with p.R241C (Pathogenic in ClinVar and by ClinGen PAH VCEP); BH4 deficiency was excluded (PMID:25894915). It has been found in trans with p.F302V (unclassified) in a Chinese patient with mild PKU (plasma Phe 360–1200 μmol/L) and BH4 deficiency excluded (PMID:30459323). It has been reported in trans with c.1066-3C>T (Pathogenic/Likely Pathogenic in ClinVar and by ClinGen PAH VCEP)in a PKU patient (PMID:23430918). The variant is absent from ethnically diverse control databases, including gnomAD/ExAC, 1000 Genomes, and ESP (PM2_supporting). The variant is predicted damaging by multiple in-silico missense predictors, including REVEL (REVEL score 0.993) (PP3).Classification: PathogenicSupporting Criteria: PS3_supporting; PM2_supporting; PM3_VeryStrong; PP4_Moderate; PP3 LINK:https://erepo.genome.network/evrepo/ui/classification/CA229855/MONDO:0009861/006

• Frequency: Genomes: not found (cov: 32)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:5 O:1
• Conservation: PhyloP100: 9.60
• Publications: 11 publications found

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]

PAH Gene-Disease associations (from GenCC):

• phenylketonuria

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen, Myriad Women’s Health
• classic phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• maternal phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• mild hyperphenylalaninemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• mild phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• tetrahydrobiopterin-responsive hyperphenylalaninemia/phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 6 ACMG points.

• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM3: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: 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.929C>T	p.Ser310Phe	missense_variant	Exon 9 of 13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.929C>T	p.Ser310Phe	missense_variant	Exon 10 of 14		NP_001341233.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6	c.929C>T	p.Ser310Phe	missense_variant	Exon 9 of 13	1	NM_000277.3	ENSP00000448059.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:5

Dec 30, 2023

ClinGen PAH Variant Curation Expert Panel

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The NM_000277.1(PAH):c.929C>T (p.Ser310Phe) variant is a missense variant in exon 9/13 of PAH. The variant has been found to result in <1% of wild-type PAH enzyme activity in a standard cDNA and an Intinc system (PMID: 18590700) (PS3_supporting). It has been found in at least 8 PKU patients, including among those whom BH4 deficiency was excluding and in trans with other Pathogenic or Likely Pathogenic alleles (PM3_VeryStrong (4.75 points); PP4_Moderate). It has been found in 2 alleles in a survey of German PKU patients (PMID: 12655553); in trans with the c.442-1G>A (Pathogenic in ClinVar and by ClinGen PAH VCEP) variant in a Korean patient with moderate PKU (plasma Phe 600-1200 umol/L) with BH4 deficiency excluded by urinary pterin analysis and dihydropteridine reductase (DHPR) assay (PMID: 15503242). It has been found in as a homozygous variant in a Syrian patient with classic PKU (plasma Phe 1262 umol/L) (PMID: 23856132). It has been found in two Chinese patients with classic PKU and BH4 deficiency excluded via analysis of urinary pterins and dihydropteridine reductase activity in erythrocytes: one harbored it in trans with the p.R111* variant (Pathogenic in ClinVar and by ClinGen PAH VCEP) and one in trans with the p.Y356* variant (Pathogenic in ClinVar and by ClinGen PAH VCEP) (PMID: 30050108). It has been found in a Chinese patient with mild hyperphenylalanemia (plasma Phe 120-360 umol/L) in trans with p.R241C (Pathogenic in ClinVar and by ClinGen PAH VCEP); BH4 deficiency was excluded (PMID: 25894915). It has been found in trans with p.F302V (unclassified) in a Chinese patient with mild PKU (plasma Phe 360–1200 μmol/L) and BH4 deficiency excluded (PMID: 30459323). It has been reported in trans with c.1066-3C>T (Pathogenic/Likely Pathogenic in ClinVar and by ClinGen PAH VCEP)in a PKU patient (PMID: 23430918). The variant is absent from ethnically diverse control databases, including gnomAD/ExAC, 1000 Genomes, and ESP (PM2_supporting). The variant is predicted damaging by multiple in-silico missense predictors, including REVEL (REVEL score 0.993) (PP3). Classification: Pathogenic Supporting Criteria: PS3_supporting; PM2_supporting; PM3_VeryStrong; PP4_Moderate; PP3 -

Oct 28, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 01, 2020

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Review of the variants reported in Reuter et al., 2017, PMID: 28097321: PM2,PM5,PM3_Strong,PP3 -

Sep 16, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jul 16, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has been reported in individuals affected with phenylketonuria or mild hyperphenylalaninemia either as homozygous or in combination with other PAH variants in many of the other cases (PMID: 15503242, 23856132, 12655553, 19915519, 26503515, 23932990). ClinVar contains an entry for this variant (Variation ID: 102899). This variant is not present in population databases (ExAC no frequency). This sequence change replaces serine with phenylalanine at codon 310 of the PAH protein (p.Ser310Phe). The serine residue is highly conserved and there is a large physicochemical difference between serine and phenylalanine. -

not provided Other:1

-

DeBelle Laboratory for Biochemical Genetics, MUHC/MCH RESEARCH INSTITUTE

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Pathogenic	4.4	H;.
PhyloP100		9.6
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-5.8	D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.99
MutPred		0.95		Loss of disorder (P = 0.0509);.;
MVP		0.99
MPC		0.25
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.98
gMVP		0.99
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs62642913; hg19: chr12-103240713;