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In this article we will discuss about the top two types of inherited diseases that are found in families. The diseases are: 1. Diabetes Mellitus 2. Muscular Dystrophies.
Disease # 1. Diabetes Mellitus:
This is a complex, heterogeneous condition which is frequently seen to recur in certain families. It is due to partial or complete lack of insulin which leads to impaired carbohydrate metabolism, as well as abnormalities in lipid and protein metabolism. Insulin is required for utilisation of glucose and for maintaining low levels of glucose in the blood.
In diabetes mellitus, the formation of glucose exceeds its utilisation giving rise to increased concentration of glucose in blood and tissues. Excess glucose appears to reach the kidneys where it forms glycoproteins resulting in proteinurea and progressive loss of renal function.
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There are two forms, juvenile and late onset diabetes. The juvenile form affects young children and has a high recurrence risk among the young children in the family. In the late onset form people in the older age groups become diabetic. The other adults in the family have a lesser chance of being affected. The recurrence risk of diabetes also varies with the diet and environment.
The juvenile form requires insulin intake for survival, while late onset diabetes can be managed by regulating diet and with drugs. The exact cause of diabetes is not known. External agents like infection with Coxsackie virus are perhaps involved with juvenile diabetes. Some other studies point toward the existence of a recessive gene.
Disease # 2. Muscular Dystrophies:
There are a group of disorders characterised in general by progressive deterioration in the structure and function of various groups of striated muscles. There are several types of muscular dystrophies of which only a few are hereditary. The Duchenne type is X-linked recessive. It appears in early childhood and the pelvic girdle muscles are first to be involved.
The limb-girdle type is autosomal recessive and becomes manifest after puberty in the second or even third decade of life. The fascio-scapulo-humoral type is autosomal dominant. Being mild, this type does not affect longevity. It involves the muscles of the face and the pectoral girdle.
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The myotonic type is also autosomal dominant but with irregular expression. There is degeneration of the muscles of the tongue and forearm, as well as atrophy of the fascial muscles. Some more clinical features such as cataract, frontal baldness and cardiac involvement are associated with this condition.
