الفهرس Only 14 pages are availabe for public view
 |  | from | 137 |  |  |
| | | from | 137 | | |
Abstract
Background: Unifactorial inheritance refers to those disorders that are due to the inheritance of a single mutant gene. It was described firstly by Mendel in 1865 and
republished by Bateson in 190 I and from their ratios for main conclusions were drawn. With time, these principles have had to be modified. For example, although most genes come in pairs, for genes on the sex chromosomes, males only have one allele, that is, they are termed hemizygous. Also, although alleles of a gene on
different chromosomes show independent assortment, genes that are physically close together on the same chromosome do not-a phenomenon that has allowed mapping of genes in the hwnan genome through linkage studies. These principles, however, still
form a useful set of rules designed to explain the inheritance of many inherited characteristics and disorders. Diseases inherited in a mendelian fashion are
categorized according to whether the gene is on an autosome or a sex chromosome and whether the trait is dominant or recessive.
Objectives: The aim of the work is to put the highlight on Mendelian inheritance. Patients and methods: Only a blood spot was needed to estimate the polyunsaturated fatty acids in the whole bloody by a pricking the thwnb and putting the drops of blood·
on dried filter paper. These dried blood spots were left to dry in the room temperature. then stored in the refrigerator. Results: There is highly significant difference between patients and control blood DHA level with 35% in patients from control DHA blood level.
Conclusion: DHA may have a role in the regeneration of rhodopsin, as it affect the transport of ll-cis-retinal component of rhodopsin by Interphotoreceptor Retinal
Binding Protein (IRBP) from the Retinal Pigmented Epithelium (RPE).