This book is aimed at anyone interested in the biological phenomenon of uniparental disomy (UPD). Since UPD can lead to congenital diseases, this is also an important topic of the book - eight testimonials from affected families are also [...] book answers the following and other questions: - What is a UPD?- What is the difference between congenital and acquired UPD?- How common is the UPD phenomenon?- How can UPD develop?- What forms and subtypes of UPD are there?- What are the clinical consequences of UPD?- Is UPD hereditary?- How can UPD be diagnosed?- What patient organizations are there?- What is imprinting and why can it be connected with UPD?- What are imprinting syndromes there?- Which research approaches are there?- Will there soon be a gene therapy for UPD?UPD has long been misunderstood as a molecular genetic problem - here it is put in its proper place as a chromosomal / chromosomic phenomenon. The book is also basis for the correct interpretation of UPD findings from molecular genetics (SNP-array-CGH or NGS).