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