Prader-Willi syndrome based MCQ | Crack AIIMS NOV 2016 MCQs

Disorders like Prader-Willi syndrome can involve changes in gene structure or modification. Which of the following processes occurs at the 5 position of cytidine and often correlates with gene inactivation?

A. Gene conversion 
B. Sister chromatid exchange
C. Pseudogene 
D. DNA methylation

Answer. D. DNA methylation

Angelman syndrome                          DCP        15

Cri du chat                                           D             5

Cystic fibrosis                                      P              7q

Down syndrome                                  C             21

Haemochromatosis                              P              6

Hemophilia                                          P              X

Klinefelter syndrome                           C             X

Neurofibromatosis                                              17q/22q

Polycystic kidney disease  P              16 (PKD1) or 4 (PKD2)

Prader–Willi syndrome                       DC          15 (CpG DNA Methylation)

Sickle-cell disease             P              11p

Tay–Sachs disease             P              15

Turner syndrome               C             X

D = deletion

C = chromosomal abbreation

P = point mutation