Question

Which of the following is not an example of recessive autosomal disease?
A. Haemophilia
B. Cystic fibrosis
C. Phenylketonuria
D. Sickle-cell anaemia

Answer 1

Hint: There are some health problems which get passed down to a child through his family. Genes are inherited from our biological parents. One in every of the essential patterns of inheritance of our genes is termed autosomal recessive inheritance.

Complete Answer:
Recessive autosomal disease can be defined as a genetic condition that appears only in individuals who have received two copies of an autosomal gene, one copy from each parent. Parents who are carriers have one copy of the gene and don't exhibit the trait because the gene is recessive to its normal counterpart gene.

If both parents are carriers, there's a 25% chance of a baby inheriting both abnormal genes and, consequently, developing the disease. There's a 50% chance of a toddler inheriting only 1 abnormal gene and of being a carrier, just like the parents, and there's a 25% chance of the kid inheriting both normal genes.

Autosomal recessive inheritance may also be defined as a gene which is found on one in all the autosomes (chromosome pairs 1 through 22). Males and females are equally affected. "Recessive" means two copies of the gene are necessary to own the trait, one inherited from the mother, and one from the daddy. Someone who has only 1 gene is alleged to be a "carrier" for the trait or disease, but they do not have any health problems from "carrying" one copy of the gene. Most people don't know they carry a factor for a disease until they need a toddler with the disease. Once parents have had a baby with a recessive trait or disease, there's a 25 percent chance, with each subsequent pregnancy, for an additional child to turn with the identical trait or disorder. This implies that there's 75 percent chance for an additional child to not have the trait or disease.

Hemophilia: Hemophilia is typically an inherited bleeding disorder during which the blood doesn't clot properly. This may result in spontaneous bleeding yet as bleeding following injuries or surgery. Blood contains numerous proteins known as clotting factors that prevent bleeding. People with hemophilia have low levels of either factor VIII (8) or factor IX (9). The severity of hemophilia that an individual has is decided by the number of thoughts about the blood. The lower the quantity of the factor, the more likely it's that bleeding will occur which might result in serious health problems.

Examples of autosomal recessive disorders include:
Phenylketonuria (commonly referred to as PKU) is an hereditary condition that increases the amount of a substance called phenylalanine within the blood. Phenylalanine may be a building block of proteins (an amino acid) that's obtained through the diet. It's found altogether proteins and in some artificial sweeteners. If PKU isn't treated, phenylalanine can build up to harmful levels within the body, causing intellectual disability and other serious health problems.

Cystic fibrosis (CF): Cystic fibrosis is one in all the foremost common inherited single gene disorders in Caucasians. People with CF secrete abnormal body fluids, including unusual sweat and a thick mucus which prevents the body from properly cleansing the lungs. The mucus interrupts the function of important organs and results in chronic infections. Classic CF also involves the pancreas and causes decreased absorption of essential nutrients.

Sickle cell anemia (SC): This is one among the foremost common, inherited single gene disorders in African-Americans. Erythrocyte disease involves the red blood cells, or hemoglobin, and their ability to hold oxygen. Normal hemoglobin cells are smooth, round, and versatile, just like the letter "O", in order that they can move through the vessels in our bodies easily. Erythrocyte hemoglobin cells are stiff and sticky, and form into the form of a sickle, or the letter "C" after they lose their oxygen. These sickle cells cluster together which causes blockage and stops movement of healthy, normal oxygen carrying blood. This blockage is what causes the painful and damaging complications of erythrocyte disease.

Therefore, the correct option is option A haemophilia.

Note: Other autosomal recessive disorders include:
• Canavan disease of the brain.
• Congenital neutropenia, a blood condition.
• Fanconi anemia, a progressive blood dyscrasia with a high risk of leukemia.
• Mucopolysaccharidosis (MPS), a series of carbohydrate storage disorders.