rs1555376645

Variant names:

• chr14-77579039-T-C
• rs1555376645
• NM_004863.4:c.398A>G

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_004863.4(SPTLC2):​c.398A>G​(p.Asn133Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,840 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict 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: SPTLC2 NM_004863.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.15
• Publications: 0 publications found

Genes affected

SPTLC2 (HGNC:11278): (serine palmitoyltransferase long chain base subunit 2) This gene encodes a long chain base subunit of serine palmitoyltransferase. Serine palmitoyltransferase, which consists of two different subunits, is the key enzyme in sphingolipid biosynthesis. It catalyzes the pyridoxal-5-prime-phosphate-dependent condensation of L-serine and palmitoyl-CoA to 3-oxosphinganine. Mutations in this gene were identified in patients with hereditary sensory neuropathy type I. [provided by RefSeq, Mar 2011]

SPTLC2 Gene-Disease associations (from GenCC):

• neuropathy, hereditary sensory and autonomic, type 1C

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen, Ambry Genetics
• hereditary sensory and autonomic neuropathy type 1

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.16624293).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004863.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SPTLC2	NM_004863.4	MANE Select	c.398A>G	p.Asn133Ser	missense	Exon 3 of 12	NP_004854.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SPTLC2	ENST00000216484.7	TSL:1 MANE Select	c.398A>G	p.Asn133Ser	missense	Exon 3 of 12	ENSP00000216484.2
	SPTLC2	ENST00000554901.1	TSL:1	c.206A>G	p.Asn69Ser	missense	Exon 2 of 9	ENSP00000452189.1
	SPTLC2	ENST00000557566.1	TSL:2	n.237A>G		non_coding_transcript_exon	Exon 2 of 2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461840 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727222

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111994

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neuropathy, hereditary sensory and autonomic, type 1C Uncertain:1

Oct 10, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. This sequence change replaces asparagine with serine at codon 133 of the SPTLC2 protein (p.Asn133Ser). The asparagine residue is moderately conserved and there is a small physicochemical difference between asparagine 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 SPTLC2-related disease. 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 tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.059
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.42
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Benign	0.17	T
Eigen	Benign	-0.14
Eigen_PC	Benign	0.081
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Uncertain	0.95	D
M_CAP	Benign	0.0066	T
MetaRNN	Benign	0.17	T
MetaSVM	Benign	-0.91	T
MutationAssessor	Benign	1.0	L
PhyloP100		3.1
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-0.49	N
REVEL	Benign	0.076
Sift	Benign	0.15	T
Sift4G	Benign	0.31	T
Polyphen		0.0020	B
Vest4		0.18
MutPred		0.46		Gain of catalytic residue at P137 (P = 0.0026)
MVP		0.13
MPC		0.41
ClinPred		0.54	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.10
gMVP		0.76
Mutation Taster		=77/23	polymorphism

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: rs1555376645; hg19: chr14-78045382;