A girl with normal milestones spend her time seeing her own hand, do not interact with others, what is the diagnosis?

Autism is diagnosed four times more often in boys than in girls. Ref: Synopsis of Psychiatry, 11e, pg 1153. Rett's syndrome is a progressive conditionthat has onset some months of normal development. During the first 5 months after, infants have age appropriate motor skills, normal head circumference and normal growth. social interaction shows expected reciprocal quality. At 6 months to 2 years of age, the child develops progressive encephalopathy. the signs often includes loss of purposeful hand movements, which are replaced by sterotypic motions, such as hand wringing etc. Ref: Synopsis of Psychiatry, 11e, pg 1166.