rs62508693

chr12-102851751-A-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.848T>A(p.Ile283Asn) variant causes a missense change. The variant allele was found at a frequency of 0.00000657 in 152,242 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. I283V) has been classified as Likely pathogenic.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:3 O:1
• Conservation: PhyloP100: 4.01

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 14 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 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 chr12-102851752-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1065381.Status of the report is reviewed_by_expert_panel, 3 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 12-102851751-A-T is Pathogenic according to our data. Variant chr12-102851751-A-T is described in ClinVar as [Pathogenic]. Clinvar id is 102877.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr12-102851751-A-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PAH	NM_000277.3	c.848T>A	p.Ile283Asn	missense_variant	8/13	ENST00000553106.6
PAH	NM_001354304.2	c.848T>A	p.Ile283Asn	missense_variant	9/14

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PAH	ENST00000553106.6	c.848T>A	p.Ile283Asn	missense_variant	8/13	1	NM_000277.3	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152242 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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 30

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152242 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74394

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: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Apr 13, 2023	- -
Pathogenic, reviewed by expert panel	curation	ClinGen PAH Variant Curation Expert Panel	Dec 09, 2018	The c.848T>A (p.Ile283Asn) variant in PAH is absent from population databases and predicted damaging with in silico predictors. It is a novel missense change in a residue where a different pathogenic variant has been identified (c.847A>T (p.Ile283Phe). It has been identified in multiple affected individuals in trans with known pathogenic variants (PMID: 9521426, 26413448), and was identified in a patient in which a defect in BH4 metabolism had been excluded. In summary, this variant meets criteria to be classified as pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PM3_strong, PM2, PM5, PP4_Moderate, PP3. -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Oct 10, 2021	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. For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Ile283 amino acid residue in PAH. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 8097423, 11161839, 24350308, 25596310). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 102877). This missense change has been observed in individual(s) with hyperphenylalaninemia (PMID: 9521426, 32668217). In at least one individual the data is consistent with the variant being in trans (on the opposite chromosome) from a pathogenic variant. This variant is not present in population databases (ExAC no frequency). This sequence change replaces isoleucine with asparagine at codon 283 of the PAH protein (p.Ile283Asn). The isoleucine residue is highly conserved and there is a large physicochemical difference between isoleucine and asparagine. -

not provided Other:1

not provided, no classification provided

literature only

DeBelle Laboratory for Biochemical Genetics, MUHC/MCH RESEARCH INSTITUTE

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.74
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
Cadd	Pathogenic	28
Dann	Uncertain	0.99
DEOGEN2	Pathogenic	0.99	D;D
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.6	H;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-5.4	D;D
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.0060	D;D
Polyphen		1.0	D;.
Vest4		0.98
MutPred		0.90		Gain of disorder (P = 0.0107);.;
MVP		1.0
MPC		0.28
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.96
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: rs62508693; hg19: chr12-103245529;