Question

Which of these is not a Mendelian disorder?

• A. Cystic fibrosis
• B. Sickle-cell anaemia
• C. Colour blindness
• D. Turner’s syndrome

Answer 1

The correct option is D Turner’s syndrome

Genetic disorders may be grouped into two categories – Mendelian disorders and chromosomal disorders.

• Mendelian disorders are mainly determined by alteration or mutation in the single gene. These disorders are transmitted to the offspring on the same lines as in the principle of inheritance. Examples - cystic fibrosis, sickle cell anaemia, colour blindness and haemophilia.
• Chromosomal disorders on the other hand are caused due to absence or excess or abnormal arrangement of one or more chromosomes. Example - Turner’s syndrome is due to chromosomal abnormality. It is characterized by 44 autosomes and only one X-chromosome.