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Amyotrophic lateral sclerosis/ Lou Gehrig’s Disease: Genetics & heredity

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Sclerosis is a generic medical term referring to the hardening or induration of tissue as a result of the body’s attempt to repair wear and tear. The condition is an autoimmune response and many scleroses can be quite debilitating especially if left untreated. Types of scleroses include multiple sclerosis, tuberous sclerosis and Amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (Lou Gehrig’s Disease)

This is a condition the affects both the brain and spinal cord, mainly targeting neurons. This neurodegenerative condition causes death of the neurons which connect the brain to the spinal cord and the rest of the body in an extremely complex network.  The disease is similar to other diseases that affect the neurons such as Parkinson’s and Muscular dystrophy. The condition affects only the body and a person’s mental faculties and cognitive abilities do not change when afflicted with this condition.  The age of onset for the condition is usually the late forties. In exceptional cases, the disease manifests itself in young children; in such cases it is called juvenile Amyotrophic lateral sclerosis.

Genetic links

Most cases of Amyotrophic lateral sclerosis are sporadic, in other words their onset is just random and not due to any hereditary factors or genetic inheritance. However, around 10% of cases are causes by a hereditary gene and studies have shown the tendency towards a family history. The majority of cases of ALS are sporadic – in other words, caused by a random mutation on a gene which is due to unknown causes. Studies have singled out a gene which is believed to be responsible for familial (hereditary) ALS in around twenty percent of cases: SOD1 (superoxide dismutase) gene.  A number of other gene mutations such as FUS, ANG, ALS2 have also been linked to the condition but the genes responsible for around thirty percent of hereditary cases are still unknown. Genetic testing and analysis of DNA from blood samples is still being carried out extensively to learn more about the genes responsible. A genetic counsellor might advise genetic testing for one of these genes or perhaps on several, depending on the health evaluation and inheritance pattern of that person. In the prenatal stage, women can have prenatal genetic testing to determine whether her unborn is carried of the disease or not –however, a genetic test can only be advised if the particular mutation in the family is know. Many companies offer genetic testing by using a simple DNA sample to determine the presence of certain disease causing genes. Such companies specialise in these kind of tests; however, ensure to confirm that they actually offer the DNA test for the specific disease you require.

The best person to advise should you think you might have a familial type of Amyotrophic lateral sclerosis is a genetic counsellor. Some general symptoms associated with ALS will be evaluated in order to determine whether these are in fact truly linked to a hereditary form of ALS or due to another disease altogether. If family members have passed away at a young age, determining any familial cause to the disease may be difficult. Most records of a family’s health history can be derived from the older members of one’s family. It is worth reiterating that most cases of ALS are not actually hereditary and that genetic tests are not diagnostic – they will provide an indication or confirm the presence of a gene however, whether the person is suffering from the disease will depend on other forms of assessment undertaken by a neurologist. Even if a genetic test result shows the person is a carrier of the gene, the treatment does not change in any way. Furthermore, since not all genes that may be involved in ALS have been identified, a negative result does not actually exclude the possibility of a familial type of ALS and the person tested negative. The individual might still have inherited a gene that causes ALS but that gene may not as yet have been identified. Scientists are currently focusing on gene therapy as a means of reversing or changing these genetic mutations but they are still very far from successfully manipulating ALS genes.

Symptoms of ALS

The first symptoms are mild and not always easily linked to the disease. At first a person begins to exhibit a diminished ability to produce loud sounds, rather the individual often slurs, develops a hoarse voice and has difficulty swallowing. This eventually degenerates until the person is unable to speak due to the weakening of muscles entailed in production of speech sounds.

Swallowing also systematically gets worse; at first, suffers typically begin eating smaller bites and less food. Eventually, even their own saliva becomes problematic to swallow. Eventually, the debilitating effects of the illness become so intense that finishing a small meal becomes extremely tiresome and frustrating to the individual. They may even refuse to eat more that the bare amount necessary to keep them alive.

Motor skills are also affected with suffers finding is hard to complete simple daily tasks like fitting on shoes or putting on a jumper.

Treating the ALS patient

If undernourishment has set, doctors need to first re-stabilize the body by inserting a feeding tube directly into the stomach (Percutaneous endoscopic gastrostomy). Unfortunately, there is no cure although the disease can be stalled from progressing or at least it progression slowed down. there is one sole drug that is FDA approved of which clinical studies have shown its effectiveness, riluzole.  The best solution recommended by doctors is something known as “symptom management” which includes nutrition management. This can help the sufferer maintain some degree of independence and improve the overall prognosis of the illness. Patients have a life expectancy of 2-5 years following diagnosis of the condition.

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