<prompt> In an Autosomal Recessive AR disorder, one parent is normal and the other is carrier and the child is also affected. What is the reasonGerm line mosaicismGenomic imprintingPenetrationUniparental disomy  <response>: Uniparental disomy refers to the situation in which 2 copies of a chromosome come from the same parent, instead of 1 copy coming from the mother, and 1 copy coming from the father. Angelman syndrome AS and Prader-Willi syndrome PWS are examples of disorders that can be caused by uniparental disomy. Reference: GHAI Essential pediatrics, 8th edition 