rs62644503

Positions:

• chr12-102852902-C-G
• chr12-102852902-C-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.755G>C​(p.Arg252Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R252Q) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:2
• Conservation: PhyloP100: 7.91

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 helix (size 8) in uniprot entity PH4H_HUMAN there are 18 pathogenic changes around while only 0 benign (100%) 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 chr12-102852902-C-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 12-102852902-C-G is Pathogenic according to our data. Variant chr12-102852902-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 932252.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PAH	NM_000277.3	c.755G>C	p.Arg252Pro	missense_variant	7/13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.755G>C	p.Arg252Pro	missense_variant	8/14		NP_001341233.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6	c.755G>C	p.Arg252Pro	missense_variant	7/13	1	NM_000277.3	ENSP00000448059	P1
PAH	ENST00000307000.7	c.740G>C	p.Arg247Pro	missense_variant	8/14	5		ENSP00000303500
PAH	ENST00000549247.6	n.514G>C		non_coding_transcript_exon_variant	1/6	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:2

Likely pathogenic, reviewed by expert panel	curation	ClinGen PAH Variant Curation Expert Panel	Mar 15, 2020	The c.755G>C (p.Arg252Pro) variant in PAH has been reported in multiple individuals with PKU (BH4 deficiency excluded, PMID: 21307867). This variant is absent in population databases. This variant was detected in trans with pathogenic variant p.Arg243Gln (PMID: 29316886). Computational evidence supports a deleterious effect. Other missense variants at the p.Arg252 amino acid are pathogenic (p.Arg252Gln/Trp/Gly). In summary, this variant meets criteria to be classified as likely pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PP4_Moderate, PM2, PM3, PM5, PP3. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 11, 2023	This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 252 of the PAH protein (p.Arg252Pro). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with hyperphenylalaninemia (PMID: 15319459, 21307867, 28982351, 29176022). ClinVar contains an entry for this variant (Variation ID: 932252). 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. This variant disrupts the p.Arg252 amino acid residue in PAH. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 2574153, 8116675, 17096675, 20082265, 25596310; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	1.0	D;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.72	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	4.1	H;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-6.7	D;D
REVEL	Pathogenic	0.97
Sift	Uncertain	0.0010	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;.
Vest4		0.95
MutPred		0.92		Loss of stability (P = 0.0259);.;
MVP		1.0
MPC		0.27
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.99
gMVP		0.99

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: rs62644503; hg19: chr12-103246680;