rs62514958

Positions:

• chr12-102846899-G-A
• chr12-102846899-G-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000277.3(PAH):​c.965C>T​(p.Ala322Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,062 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A322D) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.60

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 10 ACMG points.

• PM1: In a helix (size 12) in uniprot entity PH4H_HUMAN there are 8 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 chr12-102846899-G-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.974

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PAH	NM_000277.3	c.965C>T	p.Ala322Val	missense_variant	9/13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.965C>T	p.Ala322Val	missense_variant	10/14		NP_001341233.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6	c.965C>T	p.Ala322Val	missense_variant	9/13	1	NM_000277.3	ENSP00000448059.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461062 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726890

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

May 15, 2024

Variant summary: PAH c.965C>T (p.Ala322Val) 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 251246 control chromosomes. c.965C>T has been reported in the literature in at least one compound heterozygous individual affected with Phenylalanine Hydroxylase Deficiency (Phenylketonuria) (e.g. Sterl_2012, e.g. Hillert_2020). These data do not provide sufficient evidence alone to allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. A different variant located at the same codon (c.964G>A, p.Ala322Thr) has been classified as pathogenic, supporting a critical relevance of this residue to PAH protein function. The following publications have been ascertained in the context of this evaluation (PMID: 32668217, 22526846). No submitters have cited clinical-significance assessments for this variant to ClinVar. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	1.0	D;D
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.80	D
MetaRNN	Pathogenic	0.97	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.8	H;.
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-3.8	D;D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.020	D;D
Sift4G	Uncertain	0.044	D;D
Polyphen		1.0	D;.
Vest4		0.96
MutPred		0.80		Loss of catalytic residue at A322 (P = 0.0264);.;
MVP		0.99
MPC		0.24
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.89
gMVP		0.96

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: rs62514958; hg19: chr12-103240677; COSMIC: COSV61015140;