Question

Cri du chat syndrome is due to chromosomal change involving

• A. Duplication
• B. Inversion
• C. Deletion
• D. Translocation

Answer 1

The correct option is C Deletion

Duplication is presence of extra chromosomal segment which is attached to the normal homologous chromosome causing duplication of set of genes in the same chromosome.

Inversion is chromosomal mutation where a segment of a chromosome is reversed end to end. It occurs by introduction of break in single chromosome, its rotation by l80 degree followed by its reinsertion in the same location.

Loss of one or more nucleotide bases to the DNA segment by removal of an intercalary DNA segment is known as deletion. Cri-du-chat Syndrome characterized by mewing like cry of newborn which is caused by loss of half of the long arm of chromosome 5 causes severe developmental delay in newborn.

Rearrangement of chromosomal segment between two non homologous chromosomes is called reciprocal translocation.

So, the correct answer is 'Deletion'.