Broad palm with single palm crease is visible in a person suffering from 

A person with Down's has broad palms with a characteristic palm crease. This chromosomal disorder is due to trisomy of 21 (the presence of an additional copy of the chromosome number 21).
Individuals with Down’s syndrome often have a single crease that runs across the palm of the hand, instead of the usual two palm creases.
The affected individuals are also short statured with small, round head, furrowed tongue and partially open mouth. Physical, psychomotor and mental development is retarded.