8-18069818-T-G

Variant names:

• chr8-18069818-T-G
• rs1049874
• NM_177924.5:c.277A>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_177924.5(ASAH1):​c.277A>C​(p.Ile93Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign 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. I93V) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ASAH1 NM_177924.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -1.77
• Publications: 0 publications found

Genes affected

ASAH1 (HGNC:735): (N-acylsphingosine amidohydrolase 1) This gene encodes a member of the acid ceramidase family of proteins. Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed. Processing of this preproprotein generates alpha and beta subunits that heterodimerize to form the mature lysosomal enzyme, which catalyzes the degradation of ceramide into sphingosine and free fatty acid. This enzyme is overexpressed in multiple human cancers and may play a role in cancer progression. Mutations in this gene are associated with the lysosomal storage disorder, Farber lipogranulomatosis, and a neuromuscular disorder, spinal muscular atrophy with progressive myoclonic epilepsy. [provided by RefSeq, Oct 2015]

ASAH1 Gene-Disease associations (from GenCC):

• ASAH1-related sphingolipidosis

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Farber lipogranulomatosis

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• spinal muscular atrophy-progressive myoclonic epilepsy syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp, G2P

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in NM_177924.5
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.121083796).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ASAH1	NM_177924.5	c.277A>C	p.Ile93Leu	missense_variant	Exon 4 of 14	ENST00000637790.2	NP_808592.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ASAH1	ENST00000637790.2	c.277A>C	p.Ile93Leu	missense_variant	Exon 4 of 14	1	NM_177924.5	ENSP00000490272.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.072
BayesDel_addAF	Benign	-0.33	T
BayesDel_noAF	Benign	-0.71
CADD	Benign	0.0010
DANN	Benign	0.53
DEOGEN2	Benign	0.24	T;T;T;.;T;T;T;T;T;T;T;.;.;T;T;T;T;T;T;T;.;.;.;T
Eigen	Benign	-2.0
Eigen_PC	Benign	-2.0
FATHMM_MKL	Benign	0.014	N
LIST_S2	Benign	0.72	.;T;T;T;T;.;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;.;T;T
M_CAP	Benign	0.0034	T
MetaRNN	Benign	0.12	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.30	N;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
PhyloP100		-1.8
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-0.31	.;N;N;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Benign	0.023
Sift	Benign	0.78	.;T;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Benign	0.66	.;T;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Polyphen		0.0	B;B;B;B;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.094, 0.12, 0.14
MutPred		0.19		Loss of methylation at K92 (P = 0.0603);Loss of methylation at K92 (P = 0.0603);Loss of methylation at K92 (P = 0.0603);.;.;.;Loss of methylation at K92 (P = 0.0603);.;Loss of methylation at K92 (P = 0.0603);Loss of methylation at K92 (P = 0.0603);.;Loss of methylation at K92 (P = 0.0603);.;Loss of methylation at K92 (P = 0.0603);.;Loss of methylation at K92 (P = 0.0603);.;.;Loss of methylation at K92 (P = 0.0603);Loss of methylation at K92 (P = 0.0603);.;.;.;.;
MVP		0.20
MPC		0.0031
ClinPred		0.017	T
GERP RS		-11
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.033
gMVP		0.81
Mutation Taster		=97/3	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: rs1049874; hg19: chr8-17927327;