chr13-101055348-G-C

Position:

• chr13-101055348-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_052867.4(NALCN):​c.5164C>G​(p.Arg1722Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: NALCN NM_052867.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.13

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:42743): (NALCN antisense RNA 1)

ACMG classification

Verdict is Uncertain_significance. Variant got 3 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). The gene has 63 curated pathogenic missense variants (we use a threshold of 10). The gene has 9 curated benign missense variants. GenCC has associacion of the 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NALCN	NM_052867.4	c.5164C>G	p.Arg1722Gly	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.5164C>G	p.Arg1722Gly	missense_variant	44/44	1	NM_052867.4	ENSP00000251127.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital contractures of the limbs and face, hypotonia, and developmental delay Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Neuberg Centre For Genomic Medicine, NCGM

-

The missense variant p.R1722G in NALCN (NM_052867.2) has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. The p.R1722G variant is novel (not in any individuals) in gnomAD Exomes and is novel (not in any individuals) in 1000 Genomes. There is a moderate physicochemical difference between arginine and glycine. The p.R1722G missense variant is predicted to be damaging by both SIFT and PolyPhen2. The arginine residue at codon1722 of NALCN is conserved in all mammalian species. The nucleotide c.5164 in NALCN is predicted conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.33
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Benign	0.22	T
Eigen	Benign	-0.39
Eigen_PC	Benign	-0.22
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.95	D
M_CAP	Uncertain	0.10	D
MetaRNN	Uncertain	0.46	T
MetaSVM	Uncertain	0.22	D
MutationAssessor	Benign	0.55	N
PrimateAI	Pathogenic	0.81	D
PROVEAN	Benign	-1.6	N
REVEL	Uncertain	0.51
Sift	Uncertain	0.019	D
Sift4G	Benign	0.10	T
Polyphen		0.0010	B
Vest4		0.77
MutPred		0.38		Gain of catalytic residue at E1727 (P = 0.0141);
MVP		0.43
MPC		0.91
ClinPred		0.73	D
GERP RS		2.4
Varity_R		0.36
gMVP		0.76

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: chr13-101707700;