X-107639419-A-T

Variant names:

• chrX-107639419-A-T
• rs876661263
• NM_002764.4:c.247A>T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_002764.4(PRPS1):​c.247A>T​(p.Ser83Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000182 in 1,098,221 control chromosomes in the GnomAD database, with no homozygous occurrence. There are no hemizygote samples in GnomAD. In-silico tool predicts a benign 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. S83I) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000018 (0 hom. 0 hem.)
• Consequence: PRPS1 NM_002764.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.24
• Publications: 2 publications found

Genes affected

PRPS1 (HGNC:9462): (phosphoribosyl pyrophosphate synthetase 1) This gene encodes an enzyme that catalyzes the phosphoribosylation of ribose 5-phosphate to 5-phosphoribosyl-1-pyrophosphate, which is necessary for purine metabolism and nucleotide biosynthesis. Defects in this gene are a cause of phosphoribosylpyrophosphate synthetase superactivity, Charcot-Marie-Tooth disease X-linked recessive type 5 and Arts Syndrome. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Feb 2011]

PRPS1 Gene-Disease associations (from GenCC):

• Arts syndrome

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), PanelApp Australia
• Charcot-Marie-Tooth disease X-linked recessive 5

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Orphanet, G2P
• hearing loss, X-linked 1

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: G2P, PanelApp Australia
• phosphoribosylpyrophosphate synthetase superactivity

  Inheritance: XL Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen
• PRPS1 deficiency disorder

  Inheritance: XL Classification: DEFINITIVE Submitted by: Illumina, ClinGen
• mild phosphoribosylpyrophosphate synthetase superactivity

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• severe phosphoribosylpyrophosphate synthetase superactivity

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• X-linked intellectual disability-limb spasticity-retinal dystrophy-diabetes insipidus syndrome

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• X-linked nonsyndromic hearing loss

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.39541325).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PRPS1	NM_002764.4	c.247A>T	p.Ser83Cys	missense_variant	Exon 2 of 7	ENST00000372435.10	NP_002755.1
PRPS1	NM_001204402.2	c.-82-5758A>T		intron_variant	Intron 1 of 3		NP_001191331.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PRPS1	ENST00000372435.10	c.247A>T	p.Ser83Cys	missense_variant	Exon 2 of 7	1	NM_002764.4	ENSP00000361512.4

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 0.00000182 AC: 2 AN: 1098221 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 363577

⚠️ 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: 26401

American (AMR) AF: 0.00 AC: 0 AN: 35207

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 19386

East Asian (EAS) AF: 0.00 AC: 0 AN: 30205

South Asian (SAS) AF: 0.00 AC: 0 AN: 54149

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 40533

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4137

European-Non Finnish (NFE) AF: 0.00000238 AC: 2 AN: 842107

Other (OTH) AF: 0.00 AC: 0 AN: 46096

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000203476), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 23

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Charcot-Marie-Tooth Neuropathy X Uncertain:1

Jan 05, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces serine with cysteine at codon 83 of the PRPS1 protein (p.Ser83Cys). The serine residue is moderately conserved and there is a moderate physicochemical difference between serine and cysteine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with PRPS1-related disease. ClinVar contains an entry for this variant (Variation ID: 234860). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. -

not provided Uncertain:1

Mar 03, 2017

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The S83C variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The S83C 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. However, in silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.087
BayesDel_addAF	Uncertain	0.071	D
BayesDel_noAF	Benign	-0.14
CADD	Benign	21
DANN	Benign	0.94
DEOGEN2	Pathogenic	0.88	D;.;.;D
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Uncertain	0.91	D;D;D;D
M_CAP	Uncertain	0.16	D
MetaRNN	Benign	0.40	T;T;T;T
MetaSVM	Uncertain	0.021	D
MutationAssessor	Benign	1.4	L;.;.;.
PhyloP100		4.2
PrimateAI	Uncertain	0.78	T
PROVEAN	Benign	-2.3	N;.;.;D
REVEL	Uncertain	0.33
Sift	Benign	0.061	T;.;.;T
Sift4G	Benign	0.062	T;.;.;D
Polyphen		0.0060	B;.;.;.
Vest4		0.34
MutPred		0.42		Gain of ubiquitination at K78 (P = 0.0872);Gain of ubiquitination at K78 (P = 0.0872);Gain of ubiquitination at K78 (P = 0.0872);Gain of ubiquitination at K78 (P = 0.0872);
MVP		0.95
MPC		1.6
ClinPred		0.75	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.66
gMVP		0.93
Mutation Taster		=33/67	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: rs876661263; hg19: chrX-106882649;