Which of the following genetic or chromosomal abnormalities is correctly described
A-In sickle-cell anemia the child receives an extra chromosome during conception and, as a result, develops severe mental disabilities
B-In Down syndrome, the brain tissues of the cortex degenerate, resulting in death
C-In Tay-Sachs disease, the body start producing abnormally shaped red blood cells
D-In phenylketonuria, the body is unable to produced a critical enzyme, which results in an accumulation of persons that causes profound intellectual disabilities
D-In phenylketonuria, the body is unable to produce a critical enzyme, which results in an accumulation of phenylalanine that causes profound intellectual disabilities
The correct option among the given choices is:
D-In phenylketonuria, the body is unable to produce a critical enzyme, which results in an accumulation of phenylalanine that causes profound intellectual disabilities.
To determine the correct answer, you need to have a basic understanding of each genetic or chromosomal abnormality mentioned in the options. Let's go through each one:
A) In sickle-cell anemia, the abnormality is caused by a mutation in the hemoglobin gene, leading to the production of abnormal hemoglobin. This results in misshaped red blood cells, which can cause various symptoms, but not severe mental disabilities. Therefore, option A is not correct.
B) In Down syndrome, individuals have an extra copy of chromosome 21, also known as trisomy 21. This additional chromosome does not lead to degeneration of brain tissues in the cortex, nor does it result in death. Down syndrome is associated with certain physical characteristics and developmental delays. Hence, option B is not correct.
C) Tay-Sachs disease is a genetic disorder caused by a deficiency in an enzyme called hexosaminidase A. This deficiency leads to the accumulation of harmful substances called gangliosides in the brain and spinal cord, causing progressive neurological deterioration. However, Tay-Sachs disease does not involve the production of abnormally shaped red blood cells. Therefore, option C is not correct.
D) In phenylketonuria (PKU), individuals are unable to produce the enzyme phenylalanine hydroxylase. This enzyme is necessary for the breakdown of an amino acid called phenylalanine. Without the enzyme, phenylalanine accumulates in the body, causing brain damage and intellectual disabilities if not managed with a special diet. Therefore, option D is correct.
In conclusion, option D states the correct description of phenylketonuria (PKU) as a genetic disorder resulting in profound intellectual disabilities due to the body's inability to produce a critical enzyme.
The correct description of a genetic or chromosomal abnormality among the options provided is:
D-In phenylketonuria, the body is unable to produce a critical enzyme, which results in an accumulation of persons that causes profound intellectual disabilities.