rs1556270495

chrX-103788503-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000533.5(PLP1):c.689C>G(p.Thr230Arg) variant causes a missense change. 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 (★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: PLP1 NM_000533.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.57

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]

RAB9B (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000533.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.96

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PLP1	NM_000533.5	c.689C>G	p.Thr230Arg	missense_variant	5/7	ENST00000621218.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PLP1	ENST00000621218.5	c.689C>G	p.Thr230Arg	missense_variant	5/7	1	NM_000533.5	P1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 23

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 01, 2017

This sequence change replaces threonine with arginine at codon 230 of the PLP1 protein (p.Thr230Arg). The threonine residue is highly conserved and there is a moderate physicochemical difference between threonine and arginine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a PLP1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C15"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may alter RNA splicing, but this prediction has not been confirmed by published transcriptional studies. A different missense substitution at this codon (p.Thr230Ile) has been reported in an affected individual, but the clinical significance of this observation is not known (PMID: 21679407). In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.47
Cadd	Uncertain	24
Dann	Uncertain	0.98
DEOGEN2	Pathogenic	0.97	D;D;.
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.93	D;.;D
M_CAP	Pathogenic	0.96	D
MetaRNN	Pathogenic	0.96	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.6	M;M;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.80	T
Sift4G	Uncertain	0.0020	D;D;D
Polyphen		0.67	P;P;B
Vest4		0.84
MutPred		0.77		Gain of solvent accessibility (P = 0.026);Gain of solvent accessibility (P = 0.026);.;
MVP		0.99
ClinPred		0.97	D
GERP RS		5.4
Varity_R		0.93
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

Publications

LitVar

Other links and lift over

dbSNP: rs1556270495; hg19: chrX-103043432;