Mutations - Clinical Syndromes & Laboratory Investigations-unza

Description

This document provides an overview of several key genetic disorders, their molecular basis, and associated laboratory investigations. It begins by highlighting the prevalence of congenital anomalies and genetic abnormalities, focusing on conditions resulting from single-gene defects and chromosomal anomalies. Four specific syndromes are examined in detail. Fragile X Syndrome (FXS) is an X-linked dominant disorder caused by a CGG trinucleotide repeat expansion in the FMR1 gene, which silences it and prevents production of the FMRP protein, leading to intellectual disability and developmental problems; diagnosis involves mutation analysis of the repeat region. Huntington Disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG repeat expansion in the HTT gene, resulting in a toxic huntingtin protein; diagnosis uses PCR-based methods and Southern blot analysis. Down Syndrome is a chromosomal condition typically due to trisomy 21, leading to intellectual disability and characteristic features; diagnosis is confirmed by karyotyping to detect the extra chromosome. Dubin-Johnson Syndrome is an autosomal recessive condition characterized by conjugated hyperbilirubinaemia and jaundice, caused by mutations in the ABCC2 gene impairing bilirubin transport; diagnosis involves DNA sequence analysis and biochemical tests. The document concludes by summarizing the utility of genetic testing methods—molecular, chromosomal, and biochemical—in confirming diagnoses and assessing genetic risks. This resource is essential for biomedical science and medical students in Zambia, offering foundational knowledge for understanding genetic disease mechanisms, interpreting diagnostic test results, and applying genetic principles in clinical and laboratory settings. Use this guide to enhance your competency in genetic pathology and diagnostic approaches.