Question

An autosomal genetic disorder called ‘cri – du- chat’ is called due to
A) Deletion
B) Duplication
C) Non-disjunction
D) Mutation

Answer 1

A genetic disorder is a disease that is caused by a change or mutation, in an individual DNA sequence. These mutations can be due to an error in DNA replication. The mutation is nothing but the change that occurs in the DNA sequence. A human genome is a complex set of instructions like a recipe book, directing our growth and development.

Step by step answer: The cri-du-chat syndrome is caused by deletion of the end of the short-armed chromosome affected the genetic disorder is autosomal or sex-linked. The autosomal disorder is dominant or recessive depending upon whether one allele or both are affected, cri- du- chat syndrome also known as cat cry syndrome is caused due to monosomy of small arms of chromosome no. 5. Therefore this disorder is autosomal caused due to deletion.
Option B :duplication: Duplication is a type of mutation that involves the production of one or more copies of a gene or region of a chromosome.
Option C: Non – disjunction: non – disjunction is the failure of homogenous chromosomes or sister chromatids to separate properly during cell division.
Option D: mutation: A mutation is a change in the DNA sequence, it occurs when a DNA gene such a way as to alter the genetic message carried by that gene.
Thus, the solution is option A: Depletion.

Note: In cri-du-chat syndrome many disabilities have occurred like delayed development, small head size, low birth weight, and weak muscle tone in infancy affected individuals also have distinctive facial features including widely eyes low – set ears, small jaw, and rounded face.