My sister has been diagnosed with Ehlers-Danlos Syndrome. I've read that there are a number of strands of the syndrome. I also read that each child of an individule caring the DNA strand has a 50% chance of having it. Should I be checked for this syndrome?
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 arenât. 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 wonât 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 doesnât always means that disease will be automatically inherited. Whether or not a person develops a disease depends upon the mutated geneâs ability express itself . In other words, if a mutated gene âis strongerâ 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 wonât 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!
You should be checked by a genetic doctor. I would take your sister with you so they can compare you if they want to. You may not like the sound of that but if it helps with a diagnosis then I'd do it anyway. If nothing else then a genetic doctor can tell you what your chances are of passing it along to a child. I have it. My brother has no symptoms at all but was never tested. And yet my brother's daughter has it and has several symptoms but none as severe as mine. My dad has some symptoms but no diagnosis. He has 5 brothers and a sister - none of them have it that we know of although some have a few symptoms. You never know who will get it and who won't. If you want children then have kids if you are able to have them. If you pass it along then you'll deal with it and you'll know how to deal with it unlike a lot of us who didn't have a relative who knew they had it so we're clueless coming into it.
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