12-102852866-T-C

Variant names:

• chr12-102852866-T-C
• rs199475580
• NM_000277.3:c.791A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_000277.3(PAH):​c.791A>G​(p.His264Arg) 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. 13/22 in silico tools predict a damaging 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. H264L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.02
• Publications: 3 publications found

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]

PAH Gene-Disease associations (from GenCC):

• phenylketonuria

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen, Myriad Women’s Health
• classic phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• maternal phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• mild hyperphenylalaninemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• mild phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• tetrahydrobiopterin-responsive hyperphenylalaninemia/phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 27 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in NM_000277.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 440 curated pathogenic missense variants (we use a threshold of 10). The gene has 8 curated benign missense variants. Gene score misZ: -0.64755 (below the threshold of 3.09). Trascript score misZ: -0.0084567 (below the threshold of 3.09). GenCC associations: The gene is linked to phenylketonuria, tetrahydrobiopterin-responsive hyperphenylalaninemia/phenylketonuria, maternal phenylketonuria, classic phenylketonuria, mild phenylketonuria, mild hyperphenylalaninemia.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.976

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PAH	NM_000277.3	c.791A>G	p.His264Arg	missense_variant	Exon 7 of 13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.791A>G	p.His264Arg	missense_variant	Exon 8 of 14		NP_001341233.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6	c.791A>G	p.His264Arg	missense_variant	Exon 7 of 13	1	NM_000277.3	ENSP00000448059.1
PAH	ENST00000307000.7	c.776A>G	p.His259Arg	missense_variant	Exon 8 of 14	5		ENSP00000303500.2
PAH	ENST00000549247.6	n.550A>G		non_coding_transcript_exon_variant	Exon 1 of 6	2
PAH	ENST00000635477.1	c.-50A>G		upstream_gene_variant		5		ENSP00000489230.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Phenylketonuria Uncertain:1

Jun 14, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C25"). This variant has been observed in an individual with a positive newborn screening result for PAH-related disease (Invitae). This variant is not present in population databases (ExAC no frequency). This sequence change replaces histidine with arginine at codon 264 of the PAH protein (p.His264Arg). The histidine residue is highly conserved and there is a small physicochemical difference between histidine and arginine.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D;D
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.91	D;D
M_CAP	Pathogenic	0.66	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.8	H;.
PhyloP100		8.0
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-7.5	D;D
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.010	D;D
Vest4		0.85
ClinPred		1.0	D
GERP RS		5.7
PromoterAI		0.052	Neutral
Varity_R		0.98
gMVP		0.98
Mutation Taster		=3/97	disease causing

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

Other links and lift over

dbSNP: rs199475580; hg19: chr12-103246644;