1 Vitamin-Responsive Inherited Metabolic Disorders.- Vitamin Deficiency: Historical Perspective.- Vitamin Responsiveness or Dependency.- Genetic Control of Vitamin Metabolism.- Biochemical Role of Vitamins.- Effect of Mutation on Vitamin Function: Theoretical Possibilities.- Defects of Vitamin Transport and Coenzyme Synthesis.- Cobalamin (Vitamin B12).- Folic Acid.- Calciferol (Vitamin D).- Defects of Coenzyme-Dependent Apoenzymes.- Pyridoxine (Vitamin B6).- Biotin.- Thiamine (Vitamin B1).- Genetic Heterogeneity.- Clinical Panorama.- Mendelian Inheritance.- Prenatal Detection and Treatment.- Problems and Perspectives.- 2 Inherited Deficiency of Hypoxanthine-Guanine Phosphoribosyltransferase in X-Linked Uric Aciduria (the Lesch-Nyhan Syndrome and Its Variants).- Clinical Presentation.- Frequency.- Complete Syndrome.- Clinical Variants of the Syndrome.- Pathology.- Biochemical Characteristics.- Primary Enzyme Defect.- Secondary Enzyme Disturbances.- Properties of the Normal Enzyme.- Properties of the Mutant Enzyme.- Mechanism of Excessive Rate of Purine Synthesis.- Mechanism of Neurological Dysfunction.- Genetic Significance.- Genetic Heterogeneity.- X-Linked Inheritance.- Chemical Selection.- Somatic Cell Genetics.- Preventive Control through Prenatal Diagnosis.- Characteristics of the Heterozygous State.- Pharmacological Consequences of HPRT Deficiency.- Diagnosis of X-Linked Uric Aciduria.- Clinical Signs.- Laboratory Tests.- Heterozygote Detection.- Treatment.- General Measures.- Medications.- 3 Hereditary Hemolytic Anemia Due to Enzyme Defects of Glycolysis.- Glucose Utilization by the Red Cell.- Overall Regulation of Glycolysis.- Mass Action Ratio.- Effect of Cell Age on Metabolism.- Molecular Genetic Mechanisms of Enzyme Deficiency.- Expression of Enzyme Defects in the Red Cell and Other Tissues.- Hexokinase Deficiency.- Clinical Spectrum.- Biochemical Considerations.- Genetic Considerations.- Glucosephosphate Isomerase Deficiency.- Clinical Spectrum.- Biochemical Considerations.- Genetic Considerations.- Phosphofructokinase Deficiency.- Clinical Spectrum.- Biochemical Considerations.- Genetic Considerations.- Phosphoglycerate Kinase Deficiency.- Clinical Spectrum.- Biochemical Considerations.- Genetic Considerations.- Pyruvate Kinase Deficiency.- Clinical Spectrum.- Biochemical Considerations.- Genetic Considerations.- Other Defects of Glycolytic Enzymes in the Red Cells.- Triosephosphate Isomerase Deficiency.- Glyceraldehyde-3-phosphate Dehydrogenase Deficiency.- 2,3-Diphosphoglycerate Mutase Deficiency.- Lactate Dehydrogenase Deficiency.- 4 Population Structure of the Åland Islands, Finland.- Åland.- Location and Description.- History.- Population Composition.- Migration Analyses.- Kinship and Population Structure.- The Migration Matrix Model.- Matrimonial Migration in Åland.- Parish Endogamy.- Prediction of Kinship from Matrimonial Migration Data.- Approach to Equilibrium.- Kinship Matrices.- Geographical Factors Affecting Migration Patterns.- Isolation by Distance.- Summary.- Topology of Population Structure.- 1750–1799.- 1800–1849.- 1850–1899.- 1900–1909.- 1910–1919.- 1920–1929.- 1930–1939.- 1940–1949.- 1900–1949.- The Inclusion of Mariehamn.- Correlation between Coordinates.- Summary of Topology.- Discussion of Migration Analyses.- Biological Studies.- Genetic Analyses.- Geography and Genetic Structure.- Comparison of Genetic and Migration Inference.- Twinning in and around Åland.- Ophthalmological Studies.- The Åland Bleeder Syndrome (von Willebrand-Jürgens).- 5 Population Genetics and Health Care Delivery: The Quebec Experience.- A Short History of French Canada.- A Consanguinity Study.- Objectives.- Demographic Aspect.- Sources and Material.- Results.- Discussion: Consanguinity and the Mean Coefficient Fw.- Conclusions and Decisions.- An Isolate Study.- Objectives.- Methods.- Results.- Conclusions and Decisions.- An Inbreeding Study.- Objectives.- Material.- Results.- Discussion.- Conclusions and Decisions.- A Regional Genetic Disease.- Objectives.- The Disease.- The Isolate.- The Pedigree.- The Ancestors.- The Genetics.- Prevalence at Birth and Regional Distribution.- Conclusions and Decisions.- A Genetic Care Delivery System.- History.- Services Offered by the Network.- Research and Development in the Network.- Cost of Network.- Results of Screening.- Communications.- Conclusions and Decisions.- Summary.