X-153862685-T-G

Position:

• chrX-153862685-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_001278116.2(L1CAM):​c.3752A>C​(p.Asn1251Thr) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 24)
  • Exomes 𝑓: 9.1e-7 (0 hom. 0 hem.)
  • Failed GnomAD Quality Control
• Consequence: L1CAM NM_001278116.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.74

Genes affected

L1CAM (HGNC:6470): (L1 cell adhesion molecule) The protein encoded by this gene is an axonal glycoprotein belonging to the immunoglobulin supergene family. The ectodomain, consisting of several immunoglobulin-like domains and fibronectin-like repeats (type III), is linked via a single transmembrane sequence to a conserved cytoplasmic domain. This cell adhesion molecule plays an important role in nervous system development, including neuronal migration and differentiation. Mutations in the gene cause X-linked neurological syndromes known as CRASH (corpus callosum hypoplasia, retardation, aphasia, spastic paraplegia and hydrocephalus). Alternative splicing of this gene results in multiple transcript variants, some of which include an alternate exon that is considered to be specific to neurons. [provided by RefSeq, May 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.2943448).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
L1CAM	NM_001278116.2	c.3752A>C	p.Asn1251Thr	missense_variant	29/29	ENST00000370060.7
L1CAM	NM_000425.5	c.3752A>C	p.Asn1251Thr	missense_variant	28/28
L1CAM	NM_024003.3	c.3740A>C	p.Asn1247Thr	missense_variant	27/27
L1CAM	NM_001143963.2	c.3725A>C	p.Asn1242Thr	missense_variant	26/26

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
L1CAM	ENST00000370060.7	c.3752A>C	p.Asn1251Thr	missense_variant	29/29	5	NM_001278116.2	A1

Frequencies

GnomAD3 genomes Cov.: 24

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 9.12e-7 AC: 1 AN: 1096261 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 361735

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000247

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 24

ExAC AF: 0.0000494 AC: 6

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Spastic paraplegia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 22, 2022

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. 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. This variant has not been reported in the literature in individuals affected with L1CAM-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces asparagine, which is neutral and polar, with threonine, which is neutral and polar, at codon 1251 of the L1CAM protein (p.Asn1251Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.080
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.75	.;D;.;T;.
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Benign	0.84	T;T;.;D;T
M_CAP	Pathogenic	0.50	D
MetaRNN	Benign	0.29	T;T;T;T;T
MetaSVM	Uncertain	0.44	D
MutationAssessor	Uncertain	2.7	.;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.59	T
PROVEAN	Uncertain	-4.2	D;D;D;D;D
REVEL	Benign	0.27
Sift	Uncertain	0.0020	D;D;D;D;D
Sift4G	Uncertain	0.0040	D;D;D;D;D
Polyphen		0.17, 1.0	.;B;.;.;D
Vest4		0.48
MutPred		0.24		.;Gain of glycosylation at N1251 (P = 0.0095);.;.;.;
MVP		0.95
MPC		1.5
ClinPred		0.61	D
GERP RS		4.7
Varity_R		0.73
gMVP		0.66

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: rs201437669; hg19: chrX-153128140;