UniProtKB/Swiss-Prot P14410: Variant p.Leu341Pro

Sucrase-isomaltase, intestinal
Gene: SI
Chromosomal location: 3q25.2-q26.2
Variant information

Variant position:  341
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 Leucine (L) to Proline (P) at position 341 (L341P, p.Leu341Pro).
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:  Similar physico-chemical property. Both residues are medium size and hydrophobic.
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:  Congenital sucrase-isomaltase deficiency (CSID) [MIM:222900]: Autosomal recessive intestinal disorder that is clinically characterized by fermentative diarrhea, abdominal pain, and cramps upon ingestion of sugar. The symptoms are the consequence of absent or drastically reduced enzymatic activities of sucrase and isomaltase. The prevalence of CSID is 0.02 % in individuals of European descent and appears to be much higher in Greenland, Alaskan, and Canadian native people. CSID arises due to post-translational perturbations in the intracellular transport, polarized sorting, aberrant processing, and defective function of SI. {ECO:0000269|PubMed:10903344, ECO:0000269|PubMed:11340066, ECO:0000269|PubMed:14724820, ECO:0000269|PubMed:16329100, ECO:0000269|PubMed:8609217}. 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 CSID; causes loss of anchored SI from the membrane.
Any additional useful information about the variant.

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



Sequence information

Variant position:  341
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  1827
The length of the canonical sequence.

Location on the sequence:   LDFYILLGDTPEQVVQQYQQ  L VGLPAMPAYWNLGFQLSRWN
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                         LDFYILLGDTPEQVVQQYQQLVGLPAMPAYWNLGFQLSRWN

Rat                           LDFYIFLGDTPEQVVQQYQEVHWRPAMPAYWNLGFQLSRWN

Rabbit                        LDFYIFLGDTPEQVVQQYQELIGRPAMPAYWSLGFQLSRWN

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 2 – 1827 Sucrase-isomaltase, intestinal
Chain 2 – 1007 Isomaltase
Topological domain 33 – 1827 Lumenal
Region 110 – 1007 Isomaltase
Helix 331 – 342


Literature citations

Congenital sucrase-isomaltase deficiency arising from cleavage and secretion of a mutant form of the enzyme.
Jacob R.; Zimmer K.P.; Schmitz J.; Naim H.Y.;
J. Clin. Invest. 106:281-287(2000)
Cited for: VARIANT CSID PRO-341; CHARACTERIZATION OF VARIANT CSID PRO-341;

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.