Match List - I with List - II.

Choose the correct answer from the options given below:

(A)-(IV), (B)-(III), (C)-(II), (D)-(I)

The correct answer is Option (2) → (A)-(IV), (B)-(III), (C)-(II), (D)-(I)

A. Down’s Syndrome : The cause of this genetic disorder is the presence of an additional copy of the chromosome number 21 (trisomy of 21). This disorder was first described by Langdon Down (1866). The affected individual is short statured with small round head, furrowed tongue and partially open mouth. Palm is broad with characteristic palm crease. Physical, psychomotor and mental development is retarded.

B. Klinefelter’s Syndrome : This genetic disorder is also caused due to the presence of an additional copy of X chromosome resulting into a karyotype of 47, 44+XXY. Such an individual has overall masculine development, however, the feminine development (development of breast, i.e., Gynaecomastia) is also expressed . Such individuals are sterile.

C. Turner’s Syndrome : Such a disorder is caused due to the absence of one of the X chromosomes, i.e., 45 with XO, Such females are sterile as ovaries are rudimentary besides other features including lack of other secondary sexual characters.

D. Phenylketonuria: This inborn error of metabolism is  inherited as the autosomal recessive trait. The affected individual lacks an enzyme that converts the amino acid phenylalanine into tyrosine. As a result of this phenylalanine is accumulated and converted into phenylpyruvic acid and other derivatives.Accumulation of these in brain results in mental retardation. These are also excreted through urine because of its poor absorption by kidney.