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UniProtKB/Swiss-Prot Q13510: Variant p.Lys152Asn

Acid ceramidase
Gene: ASAH1
Variant information

Variant position:  152
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Disease [Disclaimer]
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants implicated in disease according to literature reports.
  • Polymorphism: Variants not reported to be implicated in disease.
  • Unclassified: Variants with uncertain implication in disease according to literature reports. Evidence against or in favor of a pathogenic role is limited and/or conflicting.

Residue change:  From Lysine (K) to Asparagine (N) at position 152 (K152N, p.Lys152Asn).
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 (K) to medium size and polar (N)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  0
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

Involvement in disease:  Spinal muscular atrophy with progressive myoclonic epilepsy (SMAPME) [MIM:159950]: An autosomal recessive neuromuscular disorder characterized by childhood onset of motor deficits and progressive myoclonic seizures, after normal developmental milestones. Proximal muscle weakness and generalized muscular atrophy are due to degeneration of spinal motor neurons. Myoclonic epilepsy is generally resistant to conventional therapy. The disease course is progressive and leads to respiratory muscle involvement and severe handicap or early death from respiratory insufficiency. {ECO:0000269|PubMed:22703880, ECO:0000269|PubMed:24164096, ECO:0000269|PubMed:27026573}. Note=The disease is caused by mutations affecting the gene represented in this entry.
The name and a short description of the disease associated with the variant. For more information about the disease, the user can refer to OMIM, following the link provided after the disease acronym.

Variant description:  In SMAPME; decreased protein abundance; alters the splicing of ASAH1 transcripts.
Any additional useful information about the variant.

Other resources:  
Links to websites of interest for the variant.

Sequence information

Variant position:  152
The position of the amino-acid change on the UniProtKB canonical protein sequence.

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

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.







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.

Chain 143 – 395 Acid ceramidase subunit beta
Active site 143 – 143 Nucleophile
Site 162 – 162 Important for catalytic activity
Disulfide bond 31 – 340 Interchain (between alpha and beta subunits)
Mutagenesis 141 – 141 T -> A. Decreased rate of autocatalytic processing.
Mutagenesis 143 – 143 C -> A. Loss of autocatalytic processing. Loss of ceramidase activity.
Mutagenesis 159 – 159 R -> Q. Strongly decreased autocatalytic processing. Moderately decreased ceramidase activity.
Mutagenesis 162 – 162 D -> N. Strongly decreased autocatalytic processing. Strongly decreased ceramidase activity.

Literature citations

Evidence for clinical, genetic and biochemical variability in spinal muscular atrophy with progressive myoclonic epilepsy.
Dyment D.A.; Sell E.; Vanstone M.R.; Smith A.C.; Garandeau D.; Garcia V.; Carpentier S.; Le Trionnaire E.; Sabourdy F.; Beaulieu C.L.; Schwartzentruber J.A.; McMillan H.J.; Majewski J.; Bulman D.E.; Levade T.; Boycott K.M.;
Clin. Genet. 86:558-563(2014)
Cited for: VARIANTS SMAPME ASN-152 AND 284-GLY--TRP-395 DEL;

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.