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UniProtKB/Swiss-Prot Q13510: Variant p.Arg254Gly

Acid ceramidase
Gene: ASAH1
Variant information

Variant position:  254
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  US
The variants are classified into three categories: LP/P, LB/B and US.
  • LP/P: likely pathogenic or pathogenic.
  • LB/B: likely benign or benign.
  • US: uncertain significance

Residue change:  From Arginine (R) to Glycine (G) at position 254 (R254G, p.Arg254Gly).
Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.

Physico-chemical properties:  Change from large size and basic (R) to glycine (G)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -2
The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page

Variant description:  In FRBRL; unknown pathological significance; loss of ceramidase activity.
Any additional useful information about the variant.



Sequence information

Variant position:  254
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  395
The length of the canonical sequence.

Location on the sequence:   LGILEWILGKKDVMWIGFLT  R TVLENSTSYEEAKNLLTKTK
The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.

Residue conservation: 
The multiple alignment of the region surrounding the variant against various orthologous sequences.

Human                         LGILEWILG-KKDVMWIGFLTRTVLENSTSYEEAKNLLTKTK

Chimpanzee                    LGILEWILG-KKDAMWIGFLTRTVLENSTSYEEAKNLLTKT

Mouse                         LGILEWMFG-RKDAQWVGFITRSVLENTTSYEEAKNTLTKT

Rat                           LGILEWMFG-KKNAQWVGFITRSVLENSTSYEEAKNILTKT

Bovine                        MGVMEWILG-KKDAQWVGFIIRSVLENSTSYEETKNILTKT

Caenorhabditis elegans        YGILKWVFGLEADGKWMSWLARETLETKTTYLDAKEHLMNT

Sequence annotation in neighborhood:  
The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.

TypePositionsDescription
Chain 143 – 395 Acid ceramidase subunit beta
Glycosylation 259 – 259 N-linked (GlcNAc...) asparagine
Disulfide bond 31 – 340 Interchain (between alpha and beta subunits)
Mutagenesis 259 – 259 N -> Q. Loss of ceramide catabolic process.
Helix 249 – 259


Literature citations

The human acid ceramidase gene (ASAH): structure, chromosomal location, mutation analysis, and expression.
Li C.M.; Park J.H.; He X.; Levy B.; Chen F.; Arai K.; Adler D.A.; Disteche C.M.; Koch J.; Sandhoff K.; Schuchman E.H.;
Genomics 62:223-231(1999)
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]; FUNCTION; CATALYTIC ACTIVITY; PATHWAY; VARIANTS FRBRL VAL-138; GLY-254 AND ARG-362; CHARACTERIZATION OF VARIANTS FRBRL VAL-138; GLY-254 AND ARG-362; TISSUE SPECIFICITY;

Brief Report: Peripheral Osteolysis in Adults Linked to ASAH1 (Acid Ceramidase) Mutations: A New Presentation of Farber's Disease.
Bonafe L.; Kariminejad A.; Li J.; Royer-Bertrand B.; Garcia V.; Mahdavi S.; Bozorgmehr B.; Lachman R.L.; Mittaz-Crettol L.; Campos-Xavier B.; Nampoothiri S.; Unger S.; Rivolta C.; Levade T.; Superti-Furga A.;
Arthritis Rheum. 68:2323-2327(2016)
Cited for: VARIANTS FRBRL ARG-169 AND GLY-254;

Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.