In a diploid set of chromosomes,the deletion or addition of a chromosome leads to:

When the chromosome number of a given organism has one additional chromosome in one of the homologous pairs,the addition is known as

Identify the disease on the basis of the following characters:
$(1)$ Short stature with a small round head.
$(2)$ Furrowed tongue and partially open mouth.
$(3)$ Palm is broad with a characteristic palm crease.

Loss or gain of a segment of $DNA$ results in

The given figure represents which disorder?

In humans,mental retardation is associated with sex-linked abnormalities. It is generally due to: