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UniProtKB/Swiss-Prot P08686: Variant p.Tyr191His

Steroid 21-hydroxylase
Gene: CYP21A2
Variant information

Variant position:  191
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  LP/P [Disclaimer]
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 Tyrosine (Y) to Histidine (H) at position 191 (Y191H, p.Tyr191His).
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 aromatic (Y) to medium size and polar (H)
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 AH3; exhibits low enzymatic activity toward 17-hydroxyprogesterone and progesterone.
Any additional useful information about the variant.



Sequence information

Variant position:  191
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  494
The length of the canonical sequence.

Location on the sequence:   IICYLTFGDKIKDDNLMPAY  Y KCIQEVLKTWSHWSIQIVDV
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                         IICYLTFGDKIKDDNLMPAYYKCIQEVLKTWSHWSIQIVDV

                              IICHLTFGDK--EDTLVHTFHDCVQDLMRTWEHWSIQMLDI

Mouse                         IISCLTFGDK--DSTLVQTLHDCVQDLLQAWNHWSIQILTI

Rat                           IISCLTFGDK-QDSTLLNATHSCVRDLLKAWNHWSVQILDI

Pig                           IICCLTFGDK--EDTLVHALHDCVQDLMKTWEHWSIQILDM

Bovine                        IICYLTFGNK--EDTLVHAFHDCVQDLMKTWDHWSIQILDM

Cat                           VICCLTFGDK--EDTLVHAFHDCVEDLMKSWEHWSIQVLDI

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 1 – 494 Steroid 21-hydroxylase
Helix 187 – 201


Literature citations

p.H282N and p.Y191H: 2 novel CYP21A2 mutations in Italian congenital adrenal hyperplasia patients.
Concolino P.; Mello E.; Patrosso M.C.; Penco S.; Zuppi C.; Capoluongo E.;
Metabolism 61:519-524(2012)
Cited for: VARIANTS AH3 HIS-191 AND ASN-282; CHARACTERIZATION OF VARIANTS AH3 HIS-191 AND ASN-282; FUNCTION; CATALYTIC ACTIVITY; BIOPHYSICOCHEMICAL PROPERTIES;

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.