rs779810169

Positions:

• chr9-92068054-T-A
• chr9-92068054-T-C

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BS1_Supporting BS2

The ENST00000262554.7(SPTLC1):​c.472A>T​(p.Thr158Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000171 in 1,461,756 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T158A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000017 (0 hom.)
• Consequence: SPTLC1 ENST00000262554.7 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.20

Genes affected

SPTLC1 (HGNC:11277): (serine palmitoyltransferase long chain base subunit 1) This gene encodes a member of the class-II pyridoxal-phosphate-dependent aminotransferase family. The encoded protein is the long chain base subunit 1 of serine palmitoyltransferase. Serine palmitoyltransferase converts L-serine and palmitoyl-CoA to 3-oxosphinganine with pyridoxal 5'-phosphate and is the key enzyme in sphingolipid biosynthesis. Mutations in this gene were identified in patients with hereditary sensory neuropathy type 1. Alternatively spliced variants encoding different isoforms have been identified. Pseudogenes of this gene have been defined on chromosomes 1, 6, 10, and 13. [provided by RefSeq, Jul 2013]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• BS1: Variant frequency is greater than expected in population mid. gnomad4_exome allele frequency = 0.0000171 (25/1461756) while in subpopulation MID AF= 0.000173 (1/5768). AF 95% confidence interval is 0.00008. There are 0 homozygotes in gnomad4_exome. There are 16 alleles in male gnomad4_exome subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAdExome4 at 25 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SPTLC1	NM_006415.4	c.472A>T	p.Thr158Ser	missense_variant	6/15	ENST00000262554.7	NP_006406.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SPTLC1	ENST00000262554.7	c.472A>T	p.Thr158Ser	missense_variant	6/15	1	NM_006415.4	ENSP00000262554	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000239 AC: 6 AN: 251146 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135760

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000980

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000171 AC: 25 AN: 1461756 Hom.: 0 Cov.: 32 AF XY: 0.0000220 AC XY: 16 AN XY: 727180

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: 0.000139

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000989

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ExAC AF: 0.0000330 AC: 4

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Hereditary sensory and autonomic neuropathy type 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 10, 2023

ClinVar contains an entry for this variant (Variation ID: 576860). This variant has not been reported in the literature in individuals affected with SPTLC1-related conditions. This variant is present in population databases (rs779810169, gnomAD 0.01%). This sequence change replaces threonine, which is neutral and polar, with serine, which is neutral and polar, at codon 158 of the SPTLC1 protein (p.Thr158Ser). 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 SPTLC1 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Uncertain	0.078	D
BayesDel_noAF	Uncertain	0.080
CADD	Uncertain	23
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.64	D
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.29
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.87	D
M_CAP	Uncertain	0.12	D
MetaRNN	Uncertain	0.71	D
MetaSVM	Uncertain	0.58	D
MutationAssessor	Uncertain	2.4	M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.63	T
PROVEAN	Benign	-2.0	N
REVEL	Pathogenic	0.72
Sift	Benign	0.091	T
Sift4G	Benign	0.16	T
Polyphen		0.57	P
Vest4		0.69
MutPred		0.44		Gain of disorder (P = 0.0575);
MVP		0.90
MPC		0.93
ClinPred		0.32	T
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Varity_R		0.17
gMVP		0.79

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: rs779810169; hg19: chr9-94830336;