Human Genetics and Disorders

This option is correct because black bone disease is a rare inherited genetic disorder in which the body cannot process the amino acids phenylalanine and tyrosine, which occur in protein.

This option is correct because Ochronosis is the syndrome caused by the accumulation of homogentisic acid in connective tissues.

This option is correct because chronic infantile neurologic cutaneous and articular syndrome (CINCA) is a rare genetic periodic fever syndrome, which causes uncontrolled inflammation in multiple parts of the body, starting in the newborn period.

This option is correct.

Progeria is caused by mutation in A/C genes which causes the appearance of premature aging in its sufferers.

Small intranuclear rods are seen in nemaline myopathy; nemaline myopathy is an inherited myopathy, a group of diseases that causes problems with the tone and contraction of skeletal muscles.

The role of pedigree analysis is to analyze the pattern of inheritance of a particular trait.

The nuclear genes control the synthesis of lysosomal enzymes. Thus, mutations in genes for nucleus causes lysosomal storage diseases.

Metachromatic leukodystrophy is a lysosomal storage disease that also affects sphingolipid metabolism. 

Erythroblastosis fetalis (hemolytic disease of the newborn) is the condition caused by Rh factor incompatibility between mother and fetus. When an Rh-negative mother carries an Rh-positive fetus, her immune system may produce antibodies that attack fetal red blood cells, causing severe anemia. Hemophilia is a bleeding disorder, erythropoiesis is RBC production, and myxedema is a thyroid condition.

A substitution is a mutation that exchanges one base for another that is a change in a single chemical letter such as switching an A to a G. Such a substitution could change a codon to one that encodes a different amino acid and cause a small change in the protein produced. For example sickle cell anemia is caused by a substitution in the beta-haemoglobin gene which alters a single amino acid in the protein produced. Sickle cell anemia is a disease in which your body produces abnormally shaped red blood cells. The cells are shaped like a crescent or sickle. They do not last as long as normal round red blood cells which lead to anemia.

A lethal mutation refers to any and all mutations that prevent an organism from reproducing in any way. Lethal mutations do not have to kill the organism to classify as lethal. An example of a lethal mutation in humans is Turner syndrome which is a disorder whereby the 23rd chromosome pair only contains an X chromosome. The person lives but is infertile. Turner syndrome is caused by a missing or incomplete X chromosome. People who have Turner syndrome develop as females.

In genetics a nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon or a nonsense codon in the transcribed mRNA and in a truncated, incomplete and usually nonfunctional protein product. It differs from a missense mutation which is a point mutation where a single nucleotide is changed to cause substitution of a different amino acid. Some genetic disorders such as thalassemia and DMD result from nonsense mutations.

A disorder which leads to mental retardation due to inborn error in metabolism is phenylketonuria.

Haemophilia or bleeder’s disease is a genetically inherited trait.  Mutation, which happens only in the germ cells (gametes), is inherited.