12-102855222-T-C

Variant names:

• chr12-102855222-T-C
• rs62508721
• NM_000277.3:c.620A>G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PP3 PP4 PM2_Supporting PM3_Strong

This summary comes from the ClinGen Evidence Repository: The NM_000277.3:c.620A>G variant in PAH is a missense variant predicted to cause substitution of asparagine by serine at amino acid 207 (p.Asn207Ser). This variant has been detected in at least 5 unrelated individuals with PAH deficiency (PMID:32668217, PMID:9048935). Of these individuals, one was a compound heterozygote for the variant and a likely pathogenic variant, p.Pro281Leu, in trans (phase confirmed by parental testing) (PMID:9048935), and four were compound heterozygotes for the variant and pathogenic variants, p.Ala300Ser, p.Ala403Val, p.Glu390Gly, p.Arg252Gln, in unknown phase (PMID:32668217) (3pts total, PM3_Strong). One of these individuals had plasma phenylalanine >120 μmol/L without the exclusion of a defect of BH4 cofactor metabolism (PMID:9048935) (PP4). This variant is absent in gnomAD v2.1.1 (PM2_Supporting). The computational predictor REVEL gives a score of 0.77 which is above the threshold of 0.75, evidence that correlates with impact to PAH function (PP3). There is a ClinVar entry for this variant (Variation ID: 102765, 1 star review status) with one submitter classifying the variant as pathogenic, one submitter classifying the variant as likely pathogenic, and one submitter classifying the variant as a variant of uncertain significance. In summary, this variant meets the criteria to be classified as likely pathogenic for PAH deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen PAH Variant Curation Expert Panel (Specifications Version 2.0): PM2_Supporting, PM3_Strong, PP3, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA229665/MONDO:0009861/006

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:3 U:1 O:1
• Conservation: PhyloP100: 3.27

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 Likely_pathogenic. Variant got 7 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.620A>G	p.Asn207Ser	missense_variant	Exon 6 of 13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.620A>G	p.Asn207Ser	missense_variant	Exon 7 of 14		NP_001341233.1
PAH	XM_017019370.2	c.620A>G	p.Asn207Ser	missense_variant	Exon 6 of 7		XP_016874859.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6	c.620A>G	p.Asn207Ser	missense_variant	Exon 6 of 13	1	NM_000277.3	ENSP00000448059.1
PAH	ENST00000549111.5	n.716A>G		non_coding_transcript_exon_variant	Exon 6 of 6	1
PAH	ENST00000307000.7	c.605A>G	p.Asn202Ser	missense_variant	Exon 7 of 14	5		ENSP00000303500.2
PAH	ENST00000551988.5	n.*57A>G		downstream_gene_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461804 Hom.: 0 Cov.: 34 AF XY: 0.00000275 AC XY: 2 AN XY: 727204

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3 Uncertain:1 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:3 Uncertain:1

Jul 22, 2021

Genome-Nilou Lab

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 29, 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.Asn207 amino acid residue in PAH. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 9452061, 12554741). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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: 102765). This missense change has been observed in individual(s) with hyperphenylalaninemia (PMID: 9048935, 17096675, 31332730). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 207 of the PAH protein (p.Asn207Ser). -

Aug 22, 2017

Counsyl

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 23, 2023

ClinGen PAH Variant Curation Expert Panel

Significance: Likely pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The NM_000277.3:c.620A>G variant in PAH is a missense variant predicted to cause substitution of asparagine by serine at amino acid 207 (p.Asn207Ser). This variant has been detected in at least 5 unrelated individuals with PAH deficiency (PMID: 32668217, PMID: 9048935). Of these individuals, one was a compound heterozygote for the variant and a likely pathogenic variant, p.Pro281Leu, in trans (phase confirmed by parental testing) (PMID: 9048935), and four were compound heterozygotes for the variant and pathogenic variants, p.Ala300Ser, p.Ala403Val, p.Glu390Gly, p.Arg252Gln, in unknown phase (PMID: 32668217) (3pts total, PM3_Strong). One of these individuals had plasma phenylalanine >120 μmol/L without the exclusion of a defect of BH4 cofactor metabolism (PMID: 9048935) (PP4). This variant is absent in gnomAD v2.1.1 (PM2_Supporting). The computational predictor REVEL gives a score of 0.77 which is above the threshold of 0.75, evidence that correlates with impact to PAH function (PP3). There is a ClinVar entry for this variant (Variation ID: 102765, 1 star review status) with one submitter classifying the variant as pathogenic, one submitter classifying the variant as likely pathogenic, and one submitter classifying the variant as a variant of uncertain significance. In summary, this variant meets the criteria to be classified as likely pathogenic for PAH deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen PAH Variant Curation Expert Panel (Specifications Version 2.0): PM2_Supporting, PM3_Strong, PP3, PP4. -

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	Benign	0.13
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
CADD	Uncertain	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.99	D;D
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.62	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.8	H;.
PrimateAI	Uncertain	0.55	T
PROVEAN	Uncertain	-3.7	D;D
REVEL	Pathogenic	0.77
Sift	Benign	0.18	T;T
Sift4G	Benign	0.59	T;T
Polyphen		0.92	P;.
Vest4		0.90
MutPred		0.85		Gain of catalytic residue at N207 (P = 0.0682);.;
MVP		0.98
MPC		0.21
ClinPred		0.99	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.72
gMVP		0.91

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

Publications

LitVar

Other links and lift over

dbSNP: rs62508721; hg19: chr12-103249000; COSMIC: COSV61013938; COSMIC: COSV61013938;