Step 1: Understanding the condition of trisomy 21. Trisomy of chromosome 21 leads to Down syndrome, a genetic disorder caused by an extra copy of chromosome 21.
Step 2: Symptoms of Down syndrome. Key features include: - Furrowed tongue (i) - Characteristic palm crease (ii) Other traits, such as developmental delays, may also occur.
List I | List II | ||
A | Down’s syndrome | I | 11th chormosome |
B | α-Thalassemia | II | ‘X’ chromosome |
C | β-Thalassemia | III | 21st chromosome |
D | Klinefelter’s syndrome | IV | 16th chromosome |
Find the incorrect statement among the following: n(A) In sex-linked recessive traits, the gene is transmitted from an unaffected carrier female to some of the male progeny. n(B) Accumulation of phenylpyruvic acid in the brain results in mental retardation. n(C) Individuals affected by Down’s Syndrome will have congenital heart defects and are more intelligent. n(D) Turner’s Syndrome is caused due to the absence of one X chromosome.
List-I | List-II |
(A) Thalassemia | (I) 47, XXY |
(B) Klinefelter’s syndrome | (II) Sex-linked recessive disorder |
(C) Turner’s syndrome | (III) 45, XO |
(D) Colour blindness | (IV) Autosomal recessive disease |