Principles Of Inheritance And Variation

Choose the correct statement(s) with respect to Down's syndrome

i. Down's syndrome results from non-disjunction of $21^{\text {st }}$ chromosome during gamete formation.

ii. Down's syndrome is a sex chromosomal disorder observed in immature mothers who are below the age of 18 .

iii. These patients have mild mental retardation, poor skeletal development, flat hands, stubby fingers and palms are broader.

iv. The have 44 A with XO type of karyotype.

v. The risk of giving birth to a Down Syndrome child is more in mothers who are over 45 years of age.