17-81934670-C-G

Variant names:

• chr17-81934670-C-G
• rs121918375
• NM_006907.4:c.616G>C

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PS1_Very_Strong PM2 PM5 PP3_Strong

The NM_006907.4(PYCR1):​c.616G>C​(p.Gly206Arg) variant causes a missense change. The variant allele was found at a frequency of 0.000000704 in 1,420,922 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G206W) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: PYCR1 NM_006907.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.00
• Publications: 0 publications found

Genes affected

PYCR1 (HGNC:9721): (pyrroline-5-carboxylate reductase 1) This gene encodes an enzyme that catalyzes the NAD(P)H-dependent conversion of pyrroline-5-carboxylate to proline. This enzyme may also play a physiologic role in the generation of NADP(+) in some cell types. The protein forms a homopolymer and localizes to the mitochondrion. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2013]

PYCR1 Gene-Disease associations (from GenCC):

• autosomal recessive cutis laxa type 2B

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, PanelApp Australia, Orphanet, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen
• PYCR1-related de Barsy syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, Ambry Genetics, PanelApp Australia
• geroderma osteodysplastica

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PS1: Transcript NM_006907.4 (PYCR1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-81934670-C-A is described in ClinVar as Pathogenic. ClinVar VariationId is 13191.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.98

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006907.4. 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
	PYCR1	NM_006907.4	MANE Select	c.616G>C	p.Gly206Arg	missense	Exon 5 of 7	NP_008838.2
	PYCR1	NM_001282281.2		c.697G>C	p.Gly233Arg	missense	Exon 6 of 8	NP_001269210.1
	PYCR1	NM_001282280.2		c.616G>C	p.Gly206Arg	missense	Exon 6 of 8	NP_001269209.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PYCR1	ENST00000329875.13	TSL:1 MANE Select	c.616G>C	p.Gly206Arg	missense	Exon 5 of 7	ENSP00000328858.8
	PYCR1	ENST00000619204.4	TSL:1	c.616G>C	p.Gly206Arg	missense	Exon 6 of 8	ENSP00000479793.1
	PYCR1	ENST00000337943.9	TSL:1	c.616G>C	p.Gly206Arg	missense	Exon 5 of 8	ENSP00000336579.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.04e-7 AC: 1 AN: 1420922 Hom.: 0 Cov.: 33 AF XY: 0.00000142 AC XY: 1 AN XY: 703220

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 32326

American (AMR) AF: 0.00 AC: 0 AN: 39074

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25418

East Asian (EAS) AF: 0.00 AC: 0 AN: 37170

South Asian (SAS) AF: 0.00 AC: 0 AN: 80904

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5722

European-Non Finnish (NFE) AF: 9.16e-7 AC: 1 AN: 1092074

Other (OTH) AF: 0.00 AC: 0 AN: 58824

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.33
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.86	D
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.74	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.54	D
MutationAssessor	Benign	1.6	L
PhyloP100		6.0
PrimateAI	Pathogenic	0.84	D
PROVEAN	Uncertain	-2.6	D
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.92		Loss of helix (P = 0.0041)
MVP		0.94
MPC		0.62
ClinPred		0.98	D
GERP RS		4.0
Varity_R		0.98
gMVP		0.98

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: rs121918375; hg19: chr17-79892546;