I. Name of Disorder:
The official name of the disorder is Diabetes Mellitus. Most people just know it as diabetes. There are two major classifications of diabetes mellitus; insulin-dependent (IDDM) and noninsulin-dependent (NIDDM). IDDM is more commonly known as Type 1 Diabetes, and NIDDM is known as Type 2 Diabetes (Ekoé, 2008). Type 1 diabetes is the juvenile-onset diabetes that deals with the complete destruction of β-cells of the pancreas whereas type 2 diabetes is an adult-onset disorder in which individuals suffer from an insulin deficiency (Ekoé, 2008).
II. Chromosomal location:
The main location of diabetes type 1 or IDDM is on the short arm of chromosome 6 at the band 21.3. IDDM is mostly influenced by the HLA class II region (Ekoé, 2008). Diabetes type 2 or NIDDM is located on several different chromosomes, and even different arms. The chromosomes that contain NIDDM are chromosomes 2-8, 10-13, 15, 17, 19, and 20.
III. Type of Inheritance:
Diabetes Mellitus is a multifactorial disorder; it is effects by both genes and the outside environment. Type 1 diabetes is shown to have a similarity throughout families, but there is no distinct pattern of inheritance (Savage & Bain, 2013). Geneticists are in a total controversy over the actual mode of inheritance of IDDM. There are hypotheses that it is autosomal recessive, autosomal dominant, some autosomal dominant and some autosomal recessive, intermediate gene dosage model, a heterogeneity theory, and a two-locus disorder (Rotter, 1981). The mode of inheritance that is most supported and accepted would be the heterogeneity because a single genetic disorder (IDDM) is caused by multiple alleles (Rotter, 1981). Type 1 diabetes also falls under heterogeneity because of the concordance of monozygotic twins. According to Jackson, the inheritance of type 1, IDDM is autosomal recessive susceptibility and is heterogeneous (Jackson, 1996). Type 2 diabetes also falls under heterogeneity inheritance because it is a caused by a variation of both genetic and environmental factors. It also has a frequent occurrence throughout generations, a very high rate of concordance in monozygotic twins, about 50-95%, and also it has a high frequency throughout races (Kahn et al., 1996).
IV. Frequency of Occurrence:
This disorder is very common in people of all ages. The overall likelihood of inheriting diabetes is about 10% (Holt, 2004). Since there are 2 different types of diabetes mellitus, there are different frequencies of inheritance in each. The relative genetic risk of inheriting a disease can be found by measuring the recurrence risk of a relative of the affected person divided by the risk for the entire population. This can be done by using a sibling or an offspring (Groop et al., 2008). The lower the relative genetic risk means that disorder has a higher frequency in the population. The relative genetic risk of type 1 is higher than that of type 2 meaning that the likelihood of inheriting type 2 ...