13-101055318-C-T

Position:

• chr13-101055318-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_052867.4(NALCN):​c.5194G>A​(p.Gly1732Arg) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,160 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NALCN NM_052867.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.86

Genes affected

NALCN (HGNC:19082): (sodium leak channel, non-selective) This gene encodes a voltage-independent, nonselective cation channel which belongs to a family of voltage-gated sodium and calcium channels that regulates the resting membrane potential and excitability of neurons. This family is expressed throughout the nervous system and conducts a persistent sodium leak current that contributes to tonic neuronal excitability. The encoded protein forms a channelosome complex that includes G-protein-coupled receptors, UNC-79, UNC-80, NCA localization factor-1, and src family tyrosine kinases. Naturally occurring mutations in this gene are associated with infantile neuroaxonal dystrophy, infantile hypotonia with psychomotor retardation and characteristic facies (IHPRF) syndrome, and congenital contractures of the limbs and face with hypotonia and developmental delay (CLIFAHDD) syndrome. A knockout of the orthologous gene in mice results in paralysis with a severely disrupted respiratory rhythm, and lethality within 24 hours after birth. [provided by RefSeq, Apr 2017]

NALCN-AS1 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), NALCN. . Gene score misZ 4.9555 (greater than the threshold 3.09). Trascript score misZ 6.7536 (greater than threshold 3.09). GenCC has associacion of gene with hypotonia, infantile, with psychomotor retardation and characteristic facies 1, digitotalar dysmorphism, hypotonia, infantile, with psychomotor retardation and characteristic facies, congenital contractures of the limbs and face, hypotonia, and developmental delay, Freeman-Sheldon syndrome, Sheldon-hall syndrome.
• BP4: Computational evidence support a benign effect (MetaRNN=0.32928526).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NALCN	NM_052867.4	c.5194G>A	p.Gly1732Arg	missense_variant	44/44	ENST00000251127.11	NP_443099.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NALCN	ENST00000251127.11	c.5194G>A	p.Gly1732Arg	missense_variant	44/44	1	NM_052867.4	ENSP00000251127.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461160 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726846

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: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Mar 18, 2022	ClinVar contains an entry for this variant (Variation ID: 1314243). This variant has not been reported in the literature in individuals affected with NALCN-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 1732 of the NALCN protein (p.Gly1732Arg). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt NALCN protein function. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Mar 31, 2021	Not observed in large population cohorts (Lek et al., 2016); In-silico analysis, which includes splice predictors and evolutionary conservation, is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.040
CADD	Uncertain	23
DANN	Uncertain	1.0
DEOGEN2	Benign	0.22	T
Eigen	Benign	-0.011
Eigen_PC	Benign	0.14
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.95	D
M_CAP	Uncertain	0.10	D
MetaRNN	Benign	0.33	T
MetaSVM	Uncertain	0.64	D
MutationAssessor	Benign	0.55	N
PrimateAI	Uncertain	0.74	T
PROVEAN	Benign	-1.6	N
REVEL	Uncertain	0.50
Sift	Benign	0.037	D
Sift4G	Benign	0.087	T
Polyphen		0.39	B
Vest4		0.49
MutPred		0.25		Gain of loop (P = 0.0312);
MVP		0.77
MPC		0.54
ClinPred		0.92	D
GERP RS		4.6
Varity_R		0.28
gMVP		0.74

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr13-101707670;