Mapping Genes for Asthma and Psoriasis
Title: Mapping and identifying genes for asthma
and psoriasis.
Author: Kere J.
Publication: Philos Trans R Soc Lond B Biol Sci.
2005 Aug 29;360(1460):1551-61.
Susceptibility genes for complex diseases are characterized by
reduced penetrance or frequency of manifestation of physical symptoms
due to:
- Influence of other genes
- Environmental factors
- Stochastic or random events
Recently, positional cloning efforts have pointed to several
candidate susceptibility genes in various complex diseases such
as Crohn’s disease and asthma. However, finding the genes
that regulate the disease process is difficult.
In this article, the author reviewed two examples:
- The cloning of GPR154 (GPRA) and AAA1 genes on chromosome
7 at the genetic location for susceptibility for atopy and asthma.
The susceptibility location for atopy and asthma contain 2 genes,
and only one of them encode for protein. The authors studied
its expression in biopsies of bronchial (branch of the trachea
that lead to the lungs) tissue and in mouse model of inflammation
of bronchial epithelial cells.
- The cloning of HLA-Cw6, CCHCR1 (HCR) and CDSN on chromosome
6 at PSOR1 or the majority susceptibility genetic location for
psoriasis. The strong genetic linkage between genes has made
it difficult to distinguish the effects of these 3 genes. The
authors engineered mice with two different form of HCR (diseased
form and healthy form). The result suggested that overexpression
(overly abundant) form of HCR in the skin of the mice was not
sufficient to induce psoriasis-like lesions. However, it did
induce changes in expression patterns of other genes –
a characteristic found in psoriatic skin.
Editor’s Note: Atopy is the genetic predisposition
of developing hypersensitivity reactions, such as hay fever, chronic
urticaria and asthma, upon exposure to specific antigen.
Positional cloning is cloning of a particular gene based on knowing
its position in the genetic sequence without any prior idea of
the function of the gene.
