9-92059261-C-A

Variant names:

• chr9-92059261-C-A
• rs778759719
• NM_006415.4:c.608G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_006415.4(SPTLC1):​c.608G>T​(p.Arg203Leu) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,704 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R203H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SPTLC1 NM_006415.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.77
• Publications: 1 publications found

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]

SPTLC1 Gene-Disease associations (from GenCC):

• amyotrophic lateral sclerosis 27, juvenile

  Inheritance: AD Classification: STRONG Submitted by: PanelApp Australia, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• neuropathy, hereditary sensory and autonomic, type 1A

  Inheritance: AD Classification: STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae)
• hereditary sensory and autonomic neuropathy type 1

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.943

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006415.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SPTLC1	NM_006415.4	MANE Select	c.608G>T	p.Arg203Leu	missense	Exon 7 of 15	NP_006406.1	O15269-1
	SPTLC1	NM_001281303.2		c.608G>T	p.Arg203Leu	missense	Exon 7 of 15	NP_001268232.1
	SPTLC1	NM_001368272.1		c.242G>T	p.Arg81Leu	missense	Exon 8 of 16	NP_001355201.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SPTLC1	ENST00000262554.7	TSL:1 MANE Select	c.608G>T	p.Arg203Leu	missense	Exon 7 of 15	ENSP00000262554.2	O15269-1
	SPTLC1	ENST00000953500.1		c.818G>T	p.Arg273Leu	missense	Exon 8 of 16	ENSP00000623559.1
	SPTLC1	ENST00000884978.1		c.608G>T	p.Arg203Leu	missense	Exon 7 of 16	ENSP00000555037.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461704 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727144

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39672

South Asian (SAS) AF: 0.00 AC: 0 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53374

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111926

Other (OTH) AF: 0.00 AC: 0 AN: 60390

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	D
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.3	M
PhyloP100		5.8
PrimateAI	Uncertain	0.74	T
PROVEAN	Pathogenic	-6.4	D
REVEL	Pathogenic	0.85
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Polyphen		0.97	D
Vest4		0.96
MutPred		0.67		Loss of solvent accessibility (P = 0.001)
MVP		0.93
MPC		1.1
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.94
gMVP		0.88
Mutation Taster		=6/94	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs778759719; hg19: chr9-94821543;