Evaluation of phenotypic expression of proximal 15q chromosomal region amplifications

Proximal region of the long arm of chromosome 15 (region 15q11-q13) is susceptible to occurence of deletions, duplications and inversions in the process of non-allelic homologous recombination due to the presence of five breaking points. Manifestation of these aberrations can differ depending on the parental origin of the derivative chromosome due to the presence of imprinted genes. Deletions of this region cause well-known disorders - Prader-Willi and Angelman syndromes. Phenotypic features linked to amplifications of this region (autism, developmental delay, speech delay, epilepsy, hypotonia) are variable and these amplifications are often inherited from a healthy parent. This thesis concerns itself with evaluation of phenotypic expression of amplifications of chromosomal region 15q11.2q13.3 in terms of genotype-phenotype correlation with the aim to contribute to explanation of these recurrent findings. A cohort of 36 patients with a detected amplification of this region was divided into multiple groups according to various criteria - size and gene content of the amplification, parental origin of the amplification and the presence of a second detected variant. Within these groups, we also took the number of copies and the location of the amplified region (interstitial amplification/marker..