Which genetic disorder is the result of a deletion of a section of an individuals chromosome?

William syndrome is the genetic disorder which results in deletion of section of an individual chromosome.
Another name for deletion is a deficiency or gene deletion or deletion mutation. Deletion is a mutation whereby part of the chromosome of DNA is lost during the period of DNA replication. Nucleotide can be deleted to entire piece of chromosome from a single base.
During meiosis of chromosomal crossover is where the deletion can cause an error. Frame-shift can be caused by deletion of multiples of three bases. Deletion can be caused by unequal crossing over or losses from translocation.

Its either a) or b),wind and water erosion gradually widen the canyon