| A disease caused by any abnormality in a person's | | | | Complex disease is the most common type of |
| genes or chromosomes is called a genetic disorder. | | | | genetic disorder. In these disorders, gene mutation |
| Several diseases have a genetic side to them. | | | | does not cause the disease, just increases the |
| Some genetic disorders are inherited. Since you inherit | | | | predisposition to the disease. Heart disease, obesity |
| genes from your parents, you may also inherit any | | | | and Alzheimer's disease are examples of complex |
| abnormality in the gene. That is one of the tenets of | | | | disease. Chromosomal disorders occur because of |
| genetics, the branch of biology associated with the | | | | abnormalities in the structure or number of |
| study of genes and their effects. A gene that has | | | | chromosomes. Down's syndrome and Klinefelters |
| undergone a mutation (alteration) is passed down | | | | syndrome are prime examples of these disorders. |
| through a family and the genetic disorder caused by | | | | Down's syndrome, also referred to as Trisomy 21, is |
| the mutated gene can affect children of all the | | | | a genetic disorder caused by the presence of an |
| subsequent generations. These mutations, or | | | | extra 21st chromosome. The effect of the extra |
| alterations, in genes can occur due to exposure to | | | | 21st chromosome varies greatly, depending on |
| environmental toxins or may occur randomly. Genetic | | | | whether the extra strand is present is full or parts, |
| disorders are also caused by abnormalities in the | | | | genetic history, and pure chance. Down's syndrome is |
| structure and function of chromosomes. It is | | | | characterized by some abnormality of cognitive |
| imperative to note that not all genetic disorders are | | | | ability, physical growth, and facial appearance. Some |
| inherited. Some, like Down's syndrome, occur as | | | | of the common physical features of a person with |
| isolated random incidents. | | | | Down's Syndrome include a single transverse palmar |
| Genetic disorders account for a large number of | | | | crease, instead of two, an almond shape to the |
| diseases, and can present in various ways. The most | | | | eyes, shorter limbs, poor muscle tone, a larger than |
| widely known genetic disorders are Down's | | | | normal space between the big and second toes, and |
| syndrome, Klinefelter's syndrome, sickle cell anemia | | | | a protruding tongue. Individuals with Down's |
| and spina bifida. Genetic disorders can often be lethal | | | | syndrome also have specific health concerns such as |
| or may sometimes cause conditions that need a | | | | a higher risk for congenital heart defects, recurrent |
| significant medical attention. More than 6000 genetic | | | | ear infections, and thyroid dysfunctions. |
| disorders have been identified till date. | | | | Klinefelter's syndrome is caused by the presence of |
| Genetic Disorders can be classified as | | | | an extra X sex chromosome. The main result is the |
| * Single gene disorders | | | | presence of small testes and reduced fertility. Other |
| * Complex disease | | | | physical and behavioral problems are common, though |
| * Chromosomal disorders | | | | the severity varies. It is the second most common |
| Single gene disorders occur because of one defective | | | | extra chromosomal disorder. |
| gene. These disorders are uncommon and the biology | | | | The biology behind genes and chromosomes and |
| behind them is not fully understood. Examples of this | | | | patterns of inheritance is yet to be completely |
| type of genetic disorder include muscular dystrophy | | | | deciphered. Genetics throws up interesting mysteries |
| and cystic fibrosis. | | | | every now and then. |