NM_013328.4:c.817G>C

Variant names:

• chr1-225920601-C-G
• rs562677710
• NM_013328.4:c.817G>C

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_013328.4(PYCR2):​c.817G>C​(p.Asp273His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,430 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PYCR2 NM_013328.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.56
• Publications: 0 publications found

Genes affected

PYCR2 (HGNC:30262): (pyrroline-5-carboxylate reductase 2) This gene belongs to the pyrroline-5-carboxylate reductase family. The encoded mitochondrial protein catalyzes the conversion of pyrroline-5-carboxylate to proline, which is the last step in proline biosynthesis. Alternatively spliced transcript variants have been described for this gene. [provided by RefSeq, Nov 2012]

PYCR2 Gene-Disease associations (from GenCC):

• hypomyelinating leukodystrophy 10

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Illumina, Labcorp Genetics (formerly Invitae)
• autosomal recessive primary microcephaly

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000255835 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• 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 10 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 0.94826 (below the threshold of 3.09). Trascript score misZ: 0.76229 (below the threshold of 3.09). GenCC associations: The gene is linked to autosomal recessive primary microcephaly, hypomyelinating leukodystrophy 10.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PYCR2	NM_013328.4	c.817G>C	p.Asp273His	missense_variant	Exon 7 of 7	ENST00000343818.11	NP_037460.2
PYCR2	NM_001271681.2	c.595G>C	p.Asp199His	missense_variant	Exon 6 of 6		NP_001258610.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PYCR2	ENST00000343818.11	c.817G>C	p.Asp273His	missense_variant	Exon 7 of 7	1	NM_013328.4	ENSP00000342502.6
ENSG00000255835	ENST00000432920.2	c.575+607G>C		intron_variant	Intron 5 of 7	2		ENSP00000414068.2
PYCR2	ENST00000612039.4	c.595G>C	p.Asp199His	missense_variant	Exon 6 of 6	3		ENSP00000478165.1
PYCR2	ENST00000478402.5	n.2426G>C		non_coding_transcript_exon_variant	Exon 5 of 5	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461430 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727036

African (AFR) AF: 0.00 AC: 0 AN: 33458

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86234

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111632

Other (OTH) AF: 0.00 AC: 0 AN: 60380

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jul 15, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This sequence change replaces aspartic acid, which is acidic and polar, with histidine, which is basic and polar, at codon 273 of the PYCR2 protein (p.Asp273His). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with PYCR2-related conditions. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.59
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.0
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Benign	0.019	T;.;T
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Uncertain	0.45	T;T;T
MetaSVM	Uncertain	-0.065	T
MutationAssessor	Uncertain	2.2	.;.;M
PhyloP100		7.6
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-0.96	.;.;N
REVEL	Uncertain	0.34
Sift	Uncertain	0.0020	.;.;D
Sift4G	Uncertain	0.0060	D;D;D
Polyphen		1.0	.;.;D
Vest4		0.48
MutPred		0.30		.;.;Gain of helix (P = 0.0325);
MVP		0.94
MPC		0.82
ClinPred		0.97	D
GERP RS		5.7
Varity_R		0.60
gMVP		0.68
Mutation Taster		=58/42	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs562677710; hg19: chr1-226108301;