Download Classify the following genetic disorders as being caused by addition

Classify the following genetic disorders as being caused by addition mutation, deletion mutation, or
substitution mutation. For the substitution mutations, give the normal and abnormal DNA and mRNA
base sequences, as well as the normal and abnormal amino acid coded for by those base sequences.
1.
In one patient with cystic fibrosis , a C is changed to a T at nucleotide 1609. This
converted a (CAG) to a (TAG). The protein produced by this patient had only the first
493 amino acids of the normal chain of 1480 and could not function.
2. Sickle cell anemia is an inherited condition. People with sickle cell anemia inherit two
copies of the sickle cell gene, one from each parent. The sickle cell gene makes abnormal
hemoglobin, called Hemoglobin-S.
In sickle cell anemia, the abnormal hemoglobin (Hemoglobin-S) sticks together when it
gives up its oxygen to the tissues. These clumps cause red blood cells to become stiff and
shaped like a sickle. It takes two copies of the sickle cell gene for the body to make the
abnormal hemoglobin found in sickle cell anemia; thus sickle-cell is an autosomal
recessive trait. In sickle-cell anemia, the replacement of A by T at the 17th nucleotide of
the gene for the beta chain of hemoglobin changes (GAG) to (GTG).
3. In the most common form of PKU(phenylketonuria), a TCC is changed to a ACC,
resulting in an inactive enzyme and incomplete metabolism of phenylalanine-containing
compounds such as proteins. The resulting buildup of phenylalanine can cause mental
retardation, eczema, loss of skin pigmentation, and other disorders. If detected early, the
disease is treatable by excluding foods high in phenylalanine form the diet.
4.
The replacement of C by U resulting in the formation of UAG in place of CAG in codon
number 39, and a shortened globin chain containing only 39 instead of the normal 146
amino acids in the -globin protein chain produces a protein that is functionally useless
and gives clinical symptoms of thalassaemia, which results in a low red blood cell count
(anemia) as well as Fatigue and weakness, Pale skin or jaundice (yellowing of the skin),
Protruding abdomen with enlarged spleen and liver, Dark urine, Abnormal facial bones
and poor growth, A poor appetite, and delayed puberty in adolescents.
5. Dystrophin is a protein that is an important component of skeletal muscle. The
dystrophin gene is located on the long arm of the X chromosome. It is a very large gene
spanning 2.5 million bp of genomic DNA and codes for a protein of approximately 3600
amino acids (11kb). removal of the whole or most of the dystrophin gene during DNA
replication results in Duchenne muscular dystrophy. This is a severe X-linked recessive
disorder that affects boys and is transmitted by carrier females. In affected boys there is
almost complete lack of dystrophin, muscle weakness beginning in childhood and
increasing progressively in severity so that the individual is wheel-chair bound at the age
of about 15 years. Death usually ensues in the early twenties due to respiratory muscle
involvement.
6.
Removal of a small, non-critical part of the dystrophin gene results in altered dystrophin
that causes the clinical condition of Becker muscular dystrophy in which muscle weakness
begins in adolescence and is very slowly progressive, and affected individuals may lead an
almost normal life.
7. Hemophilia A is an X-linked, recessive, bleeding disorder caused by a deficiency in a
protein factor that causes blood-clotting. Affected individuals develop a variable
phenotype of hemorrhage into joints and muscles, easy bruising, and prolonged bleeding
from wounds. This condition can result from a mutation in which CGA is converted to
TGA or when CGA is changed to CAA in the gene that codes for the clotting factor.
8. Tyrosinase-positive oculocutaneous albinism (OCA, type II) is an autosomal recessive
disorder in which the biosynthesis of melanin pigment is reduced in skin, hair, and eyes.
Although affected infants may appear at birth to have a complete absence of melanin
pigment, most patients with OCA type II acquire small amounts of pigment with age.
Individuals with OCA type II have the characteristic visual anomalies associated with
albinism, including visual problems and is caused by removal of one or more segments of
gene that result in melanin production.
9. A four nucleotide insertion in the gene that codes for the protein fibrillin results in TaySachs disease, which is an autosomal recessive genetic disorder. In its most common
variant, known as infantile Tay–Sachs disease, it causes a relentless deterioration of
mental and physical abilities that commences around six months of age and usually
results in death by the age of four.