In humans, a genetic disease (English: Genetic Disorder) occurs as a result of a difference in the arrangement of DNA from a normal part or all of it, or because of a mutation (either in a single gene) (Monogenic Disorder), or in a number of genes.
Multifactorial Inheritance Disorder
It can also result from both genetic mutations and environmental factors together, or it may result in destruction of chromosomes that affect their number, or their complete composition, and with continued attempts to reveal the secrets of the human genome, it is evident that all diseases They almost have a genetic aspect, some of which are caused by mutations of tint For both parents, and appears with the birth of the fetus, such as: Sickle Cell Disease.
Others result from acquired mutations that occur during a person’s lifetime without being passed on from the parents, and these mutations occur either by themselves, or by the influence of environmental factors.
Surrounding, such as smoking, for example, many cancers, and some forms of neurofibromatosis fall under this list.
Down syndrome The twenty-first chromosome in the cell nucleus doubles either completely or partially, so that the fetus has Down syndrome.
the growth phase will change as a result of the increase in Genetic material, and the physical characteristics of this syndrome appear, the most important of which are short stature and weak muscle strength, where the age of the mother is the only factor that has been linked to the increased probability of giving birth to a child suffering from this syndrome, but the main reason is still unknown, and it is worth noting that Childbirth rates for young women are increasing, and therefore 80% of births with Down syndrome are born to women younger than 35 years, and there is no scientific research linking parents ’habits and activities, or environmental factors with this syndrome, and it can be said as You can multiply in this chromosome arising from any parents; Approximately 5% of the cases was the source of the defect quotient of the father,  In addition to the above may be mentioned some of the people with Down’s syndrome physical attributes as follows:
- protruded tongue.
- Flat nose bridge.
- Neck short.
- The large distance separating the big toe from Talet.
The eyes are sloping upward, with oblique cracks, and white spots on the iris of the eye (Iris), as well as a skin fold on the inner corner of the eye. Mono deep wrinkles that mediate the palm of the palm. Marfan syndrome causes a mutation in the gene responsible for the production of the fibrillin-1 protein (English: Fibrillin-1) with the occurrence of Marfan Syndrome, one of the proteins that make up connective tissues, and connective tissues spread throughout the body. Accordingly, the damage done affects various locations of the body, especially the heart, blood vessels, eyes, joints, and bones, and the brain, skin, and lungs may also be affected without any deterioration in mental abilities, and it is considered one of the most important and most dangerous characteristics of Marfan syndrome.
Artery Aortic Enlargement, As for the specific physical signs of this syndrome, the following can be mentioned:
- Curvature of the spine.
- Tooth contention.
- Softness of the joints.
- Body length and beekeeping.
Signs of tension on the body not associated with obesity, or weight loss. Flat Feet (English: Flat Feet). The length of the limbs and fingers. Chest protrusion, or diving inward.