NM_000277.3:c.3G>C

Variant names:

• chr12-102917128-C-G
• rs62514893
• NM_000277.3:c.3G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

This summary comes from the ClinGen Evidence Repository: The c.3G>C (p.Met1Ile) variant in PAH is a null variant (start loss) where LOF is a known mechanism of disease. There are no known alternative start codons in other transcripts. The next in-frame Met is at amino acid 180 in exon 6. There are 49 pathogenic variants in ClinVar upstream of aa 180. The p.Met1Val variant has <3% enzyme activity as compared to wild type (PMID:9450897), confirming start loss variants lead to loss of function of the PAH enzyme without re-initiation. This variant is absent in population databases (PM2). This variant has not been reported in an affected individual in the literature to our knowledge. In summary, this variant meets criteria to be classified as likely pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PM2, PVS1. LINK:https://erepo.genome.network/evrepo/ui/classification/CA386303909/MONDO:0009861/006

• Frequency: Genomes: not found (cov: 32)
• Consequence: PAH NM_000277.3 start_lost
• Clinical Significance: Likely pathogenic reviewed by expert panel P:3
• Conservation: PhyloP100: 3.26
• Publications: 15 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 10 ACMG points.

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000277.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PAH	NM_000277.3	MANE Select	c.3G>C	p.Met1?	start_lost	Exon 1 of 13	NP_000268.1
	PAH	NM_001354304.2		c.3G>C	p.Met1?	start_lost	Exon 2 of 14	NP_001341233.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PAH	ENST00000553106.6	TSL:1 MANE Select	c.3G>C	p.Met1?	start_lost	Exon 1 of 13	ENSP00000448059.1
	PAH	ENST00000549111.5	TSL:1	n.99G>C		non_coding_transcript_exon	Exon 1 of 6
	PAH	ENST00000906695.1		c.3G>C	p.Met1?	start_lost	Exon 1 of 14	ENSP00000576754.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Likely pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
3	-	-	Phenylketonuria (3)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.58
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Benign	0.36	T
Eigen	Uncertain	0.33
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
PhyloP100		3.3
PROVEAN	Benign	-0.58	N
REVEL	Uncertain	0.62
Sift	Benign	0.036	D
Sift4G	Benign	0.15	T
Polyphen		0.53	P
Vest4		0.97
MutPred		1.0		Gain of sheet (P = 0.039)
MVP		0.97
ClinPred		0.98	D
GERP RS		5.2
PromoterAI		-0.10	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.72
gMVP		0.66
Mutation Taster		=4/196	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: rs62514893; hg19: chr12-103310906;