Myotonic dystrophy is an/a -

Autosomal dominant trait

The correct answer is Option (2) - Autosomal dominant trait

Broadly, 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. The pattern of inheritance of such Mendelian disorders can be traced in a family by the pedigree analysis.

Most common and prevalent Mendelian disorders are Haemophilia, Cystic fibrosis, Sickle- cell anaemia, Colour blindness, Phenylketonuria, Thalassemia, etc. It is important to mention here that such Mendelian disorders may be dominant or recessive. By pedigree analysis one can easily understand whether the trait in question is dominant or recessive. Similarly, the trait may also be linked to the sex chromosome as in case of haemophilia. It is evident that this X-linked recessive trait shows transmission from carrier female to male progeny.

Myotonic dystrophy : An example of an autosomal dominant condition is myotonic dystrophy. Myotonic dystrophy is an inherited disorder that causes muscle weakness and myotonia (inability of muscles to relax after use), which becomes more severe over time. Specific problems in other systems of the body can also occur.