rs62642908

chr12-102852887-C-Achr12-102852887-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.770G>T(p.Gly257Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,848 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 Pathogenic (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G257C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:4 O:1
• 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 hotspot region, there are 12 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 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 chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 12-102852887-C-A is Pathogenic according to our data. Variant chr12-102852887-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 102830.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr12-102852887-C-A is described in Lovd as [Pathogenic]. Variant chr12-102852887-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PAH	NM_000277.3	c.770G>T	p.Gly257Val	missense_variant	7/13	ENST00000553106.6
PAH	NM_001354304.2	c.770G>T	p.Gly257Val	missense_variant	8/14

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PAH	ENST00000553106.6	c.770G>T	p.Gly257Val	missense_variant	7/13	1	NM_000277.3	P1
PAH	ENST00000307000.7	c.755G>T	p.Gly252Val	missense_variant	8/14	5
PAH	ENST00000549247.6	n.529G>T		non_coding_transcript_exon_variant	1/6	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461848 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727228

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 02, 2018	Variant summary: PAH c.770G>T (p.Gly257Val) 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 246102 control chromosomes (in gnomAD). c.770G>T has been reported in the literature in multiple individuals affected with Phenylalanine Hydroxylase Deficiency (Phenylketonuria) (e.g. Liang 2014, Li 2015, Liu 2017). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in <10% of normal activity (Liang 2014). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, reviewed by expert panel	curation	ClinGen PAH Variant Curation Expert Panel	Nov 14, 2020	The c.770G>T (p.Gly257Val) variant in PAH has been reported in multiple individuals with PAH deficiency (BH4 deficiency excluded) (PMID: 26503515). This variant is absent in population databases. This variant was detected with multiple pathogenic variants: p.R408Q, p.Ser70del (PMID: 26322415); p.R111X (PMID: 14722928); p.Arg261Gln (PMID: 17502162); c.1068C>A (p.Y356*, PMID: 25894915); p.Arg252Trp, p.Arg243Gln, p.His107Arg, p.Leu255Ser (PMID: 28982351). Computational prediction tools and conservation analysis support a deleterious effect. In summary, this variant meets criteria to be classified as pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PM3_very-strong, PM2, PP4_Moderate, PP3. -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Jul 08, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Jul 25, 2017	- -

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	0.97
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.59
Cadd	Pathogenic	29
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Pathogenic	0.54	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.8	H;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-8.4	D;D
REVEL	Pathogenic	0.99
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.0030	D;D
Polyphen		1.0	D;.
Vest4		0.97
MutPred		0.97		Loss of methylation at R261 (P = 0.1138);.;
MVP		0.99
MPC		0.26
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.99
gMVP		0.97

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: rs62642908; hg19: chr12-103246665;