chr12-102852851-A-T

Variant names:

• chr12-102852851-A-T
• rs199475644
• NM_000277.3:c.806T>A

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000277.3(PAH):​c.806T>A​(p.Ile269Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,780 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I269L) 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: Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 9.32
• Publications: 1 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: Pathogenic. The variant received 19 ACMG points.

• PM1: In a hotspot region, there are 30 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 17 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 chr12-102852852-T-G is described in ClinVar as Pathogenic. ClinVar VariationId is 102842.Status of the report is reviewed_by_expert_panel, 3 stars.
• 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, 0.993
• PP5: Variant 12-102852851-A-T is Pathogenic according to our data. Variant chr12-102852851-A-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 102843.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PAH	NM_000277.3	c.806T>A	p.Ile269Asn	missense_variant	Exon 7 of 13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.806T>A	p.Ile269Asn	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.806T>A	p.Ile269Asn	missense_variant	Exon 7 of 13	1	NM_000277.3	ENSP00000448059.1
PAH	ENST00000307000.7	c.791T>A	p.Ile264Asn	missense_variant	Exon 8 of 14	5		ENSP00000303500.2
PAH	ENST00000549247.6	n.565T>A		non_coding_transcript_exon_variant	Exon 1 of 6	2
PAH	ENST00000635477.1	c.-35T>A		upstream_gene_variant		5		ENSP00000489230.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461780 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727186

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111922

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Phenylketonuria Pathogenic:2

Mar 10, 2022

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1 Other:1

-

DeBelle Laboratory for Biochemical Genetics, MUHC/MCH RESEARCH INSTITUTE

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Aug 09, 2016

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The I296N variant has previously been reported in association with classic PKU, however additional information regarding additional PAH variants identified in these patients was not reported (Guldberg et al., 1998; Zschocke et al., 1999; Acosta et al., 2001). This variant has also been reported in an individual with BH4-unresponsive phenylalanine hydroxylase deficiency who was also heterozygous for two additional pathogenic missense variants in the PAH gene, although the phase of these variants was not determined (Sarkissian et al., 2012). The I269N variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species and is expected to distort ionic interactions with L-Phenylalanine at the substrate binding site of the PAH protein (Pey et al., 2007). In silico analysis predicts this variant is probably damaging to the protein structure/function. Therefore, the I269N variant is likely pathogenic; however, the possibility that it is benign cannot be excluded. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	1.0	D;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Pathogenic	4.7	H;.
PhyloP100		9.3
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-6.5	D;D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.98
MutPred		0.96		Gain of disorder (P = 0.0266);.;
MVP		0.98
MPC		0.29
ClinPred		1.0	D
GERP RS		5.7
PromoterAI		0.015	Neutral
Varity_R		0.99
gMVP		1.0
Mutation Taster		=1/99	disease causing (ClinVar)

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: rs199475644; hg19: chr12-103246629;