Non‐pathological paternal isodisomy of chromosome 2 detected from a genome‐wide SNP scan

Uniparental disomy (UPD) occurs when both homologs of a chromosomal pair come from the father (paternal UPD) or the mother (maternal UPD). Depending on themechanismbywhich it arises [Engel, 2006; Robinson, 2000], it can lead to heterodisomy (where both homologous chromosomes from the same parent are present), isodisomy (where two copies of the same homologous chromosome from the sameparent are present), or amixof the two. UPD has been detected much more frequently for certain chro-