UniProtKB/Swiss-Prot P17405: Variant p.Cys431Arg

Sphingomyelin phosphodiesterase
Gene: SMPD1
Chromosomal location: 11p15.1-p15.4
Variant information

Variant position:  431
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 have been found in patients and disease-association is reported in literature. However, this classification is not a definitive assessment of variant pathogenicity.
  • Polymorphism: No disease-association has been reported.
  • Unclassified: Variants have been found in patients but disease-association remains unclear.

Residue change:  From Cysteine (C) to Arginine (R) at position 431 (C431R, p.Cys431Arg).
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 medium size and polar (C) to large size and basic (R)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -3
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:  Niemann-Pick disease B (NPDB) [MIM:607616]: A late-onset lysosomal storage disorder caused by failure to hydrolyze sphingomyelin to ceramide. It results in the accumulation of sphingomyelin and other metabolically related lipids in reticuloendothelial and other cell types throughout the body, leading to cell death. Clinical signs involve only visceral organs. The most constant sign is hepatosplenomegaly which can be associated with pulmonary symptoms. Patients remain free of neurologic manifestations. However, a phenotypic continuum exists between type A (basic neurovisceral) and type B (purely visceral) forms of Niemann-Pick disease, and the intermediate types encompass a cluster of variants combining clinical features of both types A and B. In Niemann-Pick disease type B, onset of the first symptoms occurs in early childhood and patients can survive into adulthood. 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 NPDB.
Any additional useful information about the variant.



Sequence information

Variant position:  431
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  629
The length of the canonical sequence.

Location on the sequence:   QAAEDRGDKVHIIGHIPPGH  C LKSWSWNYYRIVARYENTLA
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                         QAAEDRGDKVHIIGHIPPGHCLKSWSWNYYRIVARYENTLA

Mouse                         QAAENRGDKVHIIGHIPPGHCLKSWSWNYYKIIARYENTLA

Bovine                        QAAEDRGDKVHIIGHIPPGHCLKSWSWNYYRIVERYENTLA

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 47 – 629 Sphingomyelin phosphodiesterase
Disulfide bond 385 – 431


Literature citations

The demographics and distribution of type B Niemann-Pick disease: novel mutations lead to new genotype/phenotype correlations.
Simonaro C.M.; Desnick R.J.; McGovern M.M.; Wasserstein M.P.; Schuchman E.H.;
Am. J. Hum. Genet. 71:1413-1419(2002)
Cited for: VARIANTS NPDB VAL-49; TRP-92; PRO-137; ARG-157; PRO-196; CYS-200; MET-225; CYS-228; ASP-232; SER-245; ARG-248; HIS-289; ALA-323; ARG-330; ASP-357; HIS-376; LEU-376; PRO-379; VAL-413; TYR-421; ARG-431; PRO-432; CYS-435; VAL-452; ASP-456; TRP-474; LEU-475; LEU-480; VAL-485; ASN-488; SER-494; CYS-496; GLN-514; VAL-515; ARG-533; PRO-549; ASN-576; HIS-600 AND PRO-600;

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.