5 Abstract Definitive diagnosis of inherited metabolic disorders commonly depends on the measurement of enzyme activity (which is often complicated) and/or molecular genetic testing. Yet even the standard mutation analysis can bring false negative results in the case of gross chromosomal rearrangements or incorrect regulation of gene expression due to the mutations in regulatory regions. In the present study I focused on characterization of complex mutations affecting the gene encoding ornithin transcarbamylase (OTC) followed by studies of regulatory regions of OTC and GBA (the gene encoding β-glucocerebrosidase). In the first study we identified 14 novel mutations including three large deletions in a cohort of 37 patients with OTC deficiency (OTCD). Subsequently we evaluated clinical significance of all these mutations. We also found a heterozygote carrying a hypomorphic mutation and manifesting OTCD most likely due to unfavorable X-inactivation which was observed independently in three different peripheral tissues. In order to evaluate the clinical significance of a promoter variation c.-366A>G found in a family with mild OTCD we identified three alternative transcription start sites (TSSs) of human OTC and delimited the promoter. We also found a distal enhancer and performed functional analysis of both...

5 Abstract Definitive diagnosis of inherited metabolic disorders commonly depends on the measurement of enzyme activity (which is often complicated) and/or molecular genetic testing. Yet even the standard mutation analysis can bring false negative results in the case of gross chromosomal rearrangements or incorrect regulation of gene expression due to the mutations in regulatory regions. In the present study I focused on characterization of complex mutations affecting the gene encoding ornithin transcarbamylase (OTC) followed by studies of regulatory regions of OTC and GBA (the gene encoding β-glucocerebrosidase). In the first study we identified 14 novel mutations including three large deletions in a cohort of 37 patients with OTC deficiency (OTCD). Subsequently we evaluated clinical significance of all these mutations. We also found a heterozygote carrying a hypomorphic mutation and manifesting OTCD most likely due to unfavorable X-inactivation which was observed independently in three different peripheral tissues. In order to evaluate the clinical significance of a promoter variation c.-366A>G found in a family with mild OTCD we identified three alternative transcription start sites (TSSs) of human OTC and delimited the promoter. We also found a distal enhancer and performed functional analysis of both...