A mentally retarded child can have Down’s syndrome due to all except?
A. Deletion of 21st chromosome
B. Trisomy of 21st chromosome
C. Robertsonian translocation
D. Mosaic
A mentally retarded child can have Down’s syndrome due to all except?
A. Deletion of 21st chromosome
B. Trisomy of 21st chromosome
C. Robertsonian translocation
D. Mosaic