12-102852875-C-G

Variant names:

• chr12-102852875-C-G
• rs5030849
• NM_000277.3:c.782G>C

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PP3 PP4 PM5 PM3_Strong PM2

This summary comes from the ClinGen Evidence Repository: The PAH c.782G>C (p.Arg261Pro) variant has been reported in multiple affected individuals (PMID:26666653, Bh4 deficiency not ruled out, PP4). It has been detected with 5 known pathogenic variants (PM3_S). It is absent from ExAC/gnomAD. Computational evidence supports a deleterious effect. Also, p.R261Q is interpreted as pathogenic. In summary, this variant meets criteria to be classified as pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PM3_S, PM2, PM5, PP4, PP3. LINK:https://erepo.genome.network/evrepo/ui/classification/CA229759/MONDO:0009861/006

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:6 O:1
• Conservation: PhyloP100: 7.91
• Publications: 205 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 10 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.
• PM5: 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.782G>C	p.Arg261Pro	missense_variant	Exon 7 of 13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.782G>C	p.Arg261Pro	missense_variant	Exon 8 of 14		NP_001341233.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6	c.782G>C	p.Arg261Pro	missense_variant	Exon 7 of 13	1	NM_000277.3	ENSP00000448059.1
PAH	ENST00000307000.7	c.767G>C	p.Arg256Pro	missense_variant	Exon 8 of 14	5		ENSP00000303500.2
PAH	ENST00000549247.6	n.541G>C		non_coding_transcript_exon_variant	Exon 1 of 6	2
PAH	ENST00000635477.1	c.-59G>C		upstream_gene_variant		5		ENSP00000489230.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461846 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727230

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111982

Other (OTH) AF: 0.00 AC: 0 AN: 60388

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00131091), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:4

Jan 19, 2016

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Aug 11, 2019

ClinGen PAH Variant Curation Expert Panel

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The PAH c.782G>C (p.Arg261Pro) variant has been reported in multiple affected individuals (PMID: 26666653, Bh4 deficiency not ruled out, PP4). It has been detected with 5 known pathogenic variants (PM3_S). It is absent from ExAC/gnomAD. Computational evidence supports a deleterious effect. Also, p.R261Q is interpreted as pathogenic. In summary, this variant meets criteria to be classified as pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PM3_S, PM2, PM5, PP4, PP3. -

Jul 10, 2024

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: PAH c.782G>C (p.Arg261Pro) 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 was absent in 251358 control chromosomes. c.782G>C has been reported in the literature in multiple individuals affected with Phenylalanine Hydroxylase Deficiency (Phenylketonuria), including as a compound heterozygous phenotype (e.g. Jeannesson-Thivisol_2015). These data indicate that the variant is likely to be associated with disease. A different variant affecting the same codon has been classified as pathogenic by our lab (c.782G>A, p.Arg261Gln), supporting the critical relevance of codon 261 to PAH protein function. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in ~10% of normal enzyme activity in vitro (e.g. Trunzo_2016). The following publications have been ascertained in the context of this evaluation (PMID: 26666653, 27620137). ClinVar contains an entry for this variant (Variation ID: 102832). Based on the evidence outlined above, the variant was classified as pathogenic. -

Jun 11, 2022

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. This variant disrupts the p.Arg261 amino acid residue in PAH. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 2574153, 16765994). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects PAH function (PMID: 27620137). 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 expected to disrupt PAH protein function. ClinVar contains an entry for this variant (Variation ID: 102832). This missense change has been observed in individuals with phenylketonuria (PMID: 32668217). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 261 of the PAH protein (p.Arg261Pro). -

not provided Pathogenic:2 Other:1

-

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

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	0.56	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	1.0	D;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.62	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	4.7	H;.
PhyloP100		7.9
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-6.4	D;D
REVEL	Pathogenic	0.98
Sift	Uncertain	0.013	D;D
Sift4G	Uncertain	0.015	D;D
Polyphen		1.0	D;.
Vest4		0.97
MutPred		0.96		Loss of methylation at R261 (P = 0.0162);.;
MVP		0.99
MPC		0.26
ClinPred		1.0	D
GERP RS		5.7
PromoterAI		-0.020	Neutral
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: rs5030849; hg19: chr12-103246653;