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UniProtKB/Swiss-Prot P36021: Variant p.Leu438Pro

Monocarboxylate transporter 8
Gene: SLC16A2
Variant information

Variant position:  438
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 438 (L438P, p.Leu438Pro).
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:  Monocarboxylate transporter 8 deficiency (MCT8 deficiency) [MIM:300523]: Consists of a severe form of X-linked psychomotor retardation combined with abnormal thyroid hormone (TH) levels. Thyroid hormone deficiency can be caused by defects of hormone synthesis and action, but it has also been linked to a defect in cellular hormone transport. Affected patients are males with abnormal relative concentrations of three circulating iodothyronines, as well as severe neurological abnormalities, including global developmental delay, central hypotonia, spastic quadriplegia, dystonic movements, rotary nystagmus, and impaired gaze and hearing. Heterozygous females had a milder thyroid phenotype and no neurological defects. {ECO:0000269|PubMed:14661163, ECO:0000269|PubMed:15488219, ECO:0000269|PubMed:15889350, ECO:0000269|PubMed:18636565, ECO:0000269|PubMed:23550058, ECO:0000269|PubMed:25380603, ECO:0000269|PubMed:25527620, ECO:0000269|PubMed:26426690, ECO:0000269|PubMed:27805744, ECO:0000269|Ref.8}. 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 MCT8 deficiency; does not affect homodimerization activity.
Any additional useful information about the variant.

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



Sequence information

Variant position:  438
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  539
The length of the canonical sequence.

Location on the sequence:   LFLGLCDGFFITIMAPIAFE  L VGPMQASQAIGYLLGMMALP
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                         LFLGLCDGFFITIMAPIAFELVGPMQASQAIGYLLGMMALP

Mouse                         LFLGLCDGFFITIMAPIAFELVGPMQASQAIGYLLGMMALP

Rat                           LFLGLCDGFFITIMAPIAFELVGPMQASQAIGYLLGMMALP

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 – 539 Monocarboxylate transporter 8
Topological domain 431 – 447 Cytoplasmic


Literature citations

A novel syndrome combining thyroid and neurological abnormalities is associated with mutations in a monocarboxylate transporter gene.
Dumitrescu A.M.; Liao X.-H.; Best T.B.; Brockmann K.; Refetoff S.;
Am. J. Hum. Genet. 74:168-175(2004)
Cited for: VARIANT MCT8 DEFICIENCY PRO-438;

Modulation of monocarboxylate transporter 8 oligomerization by specific pathogenic mutations.
Fischer J.; Kleinau G.; Mueller A.; Kuehnen P.; Zwanziger D.; Kinne A.; Rehders M.; Moeller L.C.; Fuehrer D.; Grueters A.; Krude H.; Brix K.; Biebermann H.;
J. Mol. Endocrinol. 54:39-50(2015)
Cited for: VARIANTS MCT8 DEFICIENCY THR-150; HIS-197; CYS-371 AND ASP-484; CHARACTERIZATION OF VARIANTS MCT8 DEFICIENCY PHE-120; THR-150; VAL-150; PHE-156 DEL; MET-161; HIS-197; TRP-360; CYS-371 PRO-397; PRO-438; ASP-484 AND PRO-494; SUBUNIT; SUBCELLULAR LOCATION;

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.