X-103787904-T-G

Variant names:

• chrX-103787904-T-G
• rs132630288
• NM_000533.5:c.560T>G

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_000533.5(PLP1):​c.560T>G​(p.Ile187Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic 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. I187T) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 22)
• Consequence: PLP1 NM_000533.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.67
• Publications: 11 publications found

Genes affected

PLP1 (HGNC:9086): (proteolipid protein 1) This gene encodes a transmembrane proteolipid protein that is the predominant component of myelin. The encoded protein may play a role in the compaction, stabilization, and maintenance of myelin sheaths, as well as in oligodendrocyte development and axonal survival. Mutations in this gene cause Pelizaeus-Merzbacher disease and spastic paraplegia type 2. Alternatively splicing results in multiple transcript variants, including the DM20 splice variant. [provided by RefSeq, Feb 2015]

ENSG00000288597 (HGNC:):

RAB9B (HGNC:14090): (RAB9B, member RAS oncogene family) This gene encodes a member of a subfamily of RAS small guanosine triphosphate (GTP)-binding proteins that regulate membrane trafficking. The encoded protein may be involved in endosome-to-Golgi transport. [provided by RefSeq, Jan 2010]

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_000533.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrX-103787904-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 11085.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 40 curated pathogenic missense variants (we use a threshold of 10). The gene has 4 curated benign missense variants. Trascript score misZ: NaN (below the threshold of 3.09). GenCC associations: The gene is linked to hereditary spastic paraplegia 2, Pelizeaus-Merzbacher spectrum disorder, Pelizaeus-Merzbacher disease in female carriers, null syndrome, Pelizaeus-Merzbacher disease, transitional form, Pelizaeus-Merzbacher disease, classic form, Pelizaeus-Merzbacher disease, connatal form.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.973

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PLP1	NM_000533.5	c.560T>G	p.Ile187Ser	missense_variant	Exon 4 of 7	ENST00000621218.5	NP_000524.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PLP1	ENST00000621218.5	c.560T>G	p.Ile187Ser	missense_variant	Exon 4 of 7	1	NM_000533.5	ENSP00000484450.1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 22

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia 2 Uncertain:1

Apr 22, 2019

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This sequence change replaces isoleucine with serine at codon 187 of the PLP1 protein (p.Ile187Ser). The isoleucine residue is highly conserved and there is a large physicochemical difference between isoleucine and serine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with PLP1-related conditions. This variant disrupts the p.Ile187 (also known as p.Ile186) amino acid residue in PLP1. Other variant(s) that disrupt this residue have been observed in individuals with PLP1-related conditions (PMID: 7522741, 23344956, 24139698), suggesting that it is a clinically significant residue. As a result, variants that disrupt this residue are likely to be causative of disease. 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	0.98
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.98	D;D;.
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D;.;D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.97	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Benign	2.0	M;M;.
PhyloP100		7.7
PrimateAI	Uncertain	0.61	T
Sift4G	Uncertain	0.0060	D;D;D
Polyphen		0.98	D;D;P
Vest4		0.73
MutPred		0.83		Gain of disorder (P = 3e-04);Gain of disorder (P = 3e-04);.;
MVP		0.99
ClinPred		0.98	D
GERP RS		5.6
Varity_R		0.85
gMVP		0.98
Mutation Taster		=25/75	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: rs132630288; hg19: chrX-103042833;