Not true among the following is: (A) Most common cause of Down's syndrome is Maternal meiotic disjunction., (B) Most Common inherited condition causing Intellectual disability in Fragile X Syndrome, (C) The mandible in Down's child is smaller than usual, (D) Isolated finding of simian crease in Down's in seen in almost 20% of Down's children.
Answer is D. Isolated finding of simian crease in Down's in seen in almost 1% of Down's children. So it is not a significant finding in a Down's child.