Genetic Disorders Forum - Ehlers-Danlos Syndrome - have genes & genetics been passed to me

A gene is a DNA-sequence that is responsible for the synthesis of a specific protein that has specific function in the body. Genes, in fact, contain information on the synthesis of all proteins. Proteins are complex molecules that play important roles in all the metabolic processes of the body. There are more than 100.000 genes in just one cell. All the cells in ones body carry the same genes but, depending upon the type of cell, some genes are active and some aren’t. Genes are inherited from the parents when a spermatozoid fertilizes the egg-cell and a zygote is formed. By dividing the zygote and differentiating the newly created cells, a whole new organism will be created. All the cells in that new organism contain the same genes as the fist cell - the zygote. Half of the genes are inherited from the father (carried by the spermatozoid) and the other half are inherited from the mother (carried by the egg-cell). Each gene in the new organism consists of 2 copies. One copy originates from the father and the other one originates from the mother. This means that a spermatozoid and egg-cell in fact carry only one copy of all the genes. Each copy of a gene acts as an independent gene with the same function. Only the sex-cells have a single copy of the genes. In other cells, each gene is represented by 2 copies. If both copies of a particular gene are the same, it is in a HOMOZYGOTE state. If one copy is different from the original (mutated) it is in a HETEROZYGOTE state. Mutated genes are usually defective and they can cause genetic diseases if they are inherited by the next generation.

Genetic diseases are caused by the presence of one or more mutated and defective genes. If a defected (mutated) gene is present, protein molecules won’t be synthesized or will also be defective so the function of the protein will be compromised (disease).Genetic diseases can be determined by a single gene or by a group of genes. When only a single gene is responsible, inheritance and expression of the disease can be easily explained. If a group of genes is responsible, mechanisms for inheritance and expression are much more complicated.

Inheriting a defected gene doesn’t always means that disease will be automatically inherited. Whether or not a person develops a disease depends upon the mutated gene’s ability express itself . In other words, if a mutated gene “is stronger” than the original gene, disease is possible. In cases when only one gene is responsible for a genetic disorder, there are 2 types of genetic inheritance and disease expressions:

1. If a mutated gene copy is weaker than the original gene copy, then in order for a disease to occur, both copies of the gene have to be mutated (homozygote). This is called RECESSIVE inheritance. To inherit genetic disorder with such type of inheritance, both parents have to carry the defective gene. If only one parent carries the defect gene, the chances for inheriting the defect are 50% ... but the disease won’t occur. If both parents are carriers of the defective gene, the chances for inheriting the defect are 75% but chances that the disease will occur are 25%.
2. If a mutated gene is stronger than the original gene, only one mutated copy of the gene will be enough to provoke disease occurrence (heterozygote). Any carrier of the mutated gene will be ill too. Inheritance of the defective gene will automatically mean inheritance of the disease. If only one parent is carrier (and ill at the same time), the chances for inheriting the gene and the disease are 50%. If both parents are carriers the chances for inheriting the disease are 75%.

There are several forms of Ehlers-Danlos Syndrome and for each form a different but single gene is responsible for the disease. In cthe ase of Ehlers-Danlos Syndrome, a defective gene compromises the synthesis of the protein COLLAGEN. Most of the forms of Ehlers-Danlos Syndrome are inherited according to the DOMINANT pattern. Given the symptoms you describe, you can be checked for Ehlers-Danlos Syndrome!

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