Related Experiment Video
Updated: May 24, 2026
07:15
Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
Published on: January 16, 2019
Genetics of complex diseases: variations on a theme
Erling Mellerup1, Gert Lykke Møller, Pernille Koefoed
1Laboratory of Neuropsychiatry, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark. mellerup@sund.ku.dk
Medical Hypotheses
|March 20, 2012
Summary
Complex genetic diseases, like bipolar disorder, arise from multiple DNA changes. Genetic heterogeneity means numerous distinct genetic profiles (genotypes) can cause the same disease, potentially matching the number of patients.
Area of Science:
- Genetics
- Molecular Biology
- Psychiatry
Background:
- Polygenic diseases involve multiple DNA variations.
- Genetic heterogeneity means various genotypes can cause a single disease.
- Bipolar disorder serves as a model for complex inheritable conditions.
Purpose of the Study:
- To explore the concept of genetic heterogeneity in complex diseases.
- To hypothesize about the potential number of distinct genotypes for a polygenic disorder.
- To investigate the genetic underpinnings of bipolar disorder.
Main Methods:
- Review of genetic principles for complex diseases.
- Analysis of genetic variation in bipolar disorder.
- Hypothetical modeling of genotype combinations.
Main Results:
- Polygenic diseases are characterized by multiple DNA changes.
- Genetic heterogeneity suggests numerous independent genetic causes for a disease.
- The number of potential genotypes may be vast, approaching the number of affected individuals.
Conclusions:
- Complex inheritable diseases exhibit significant genetic heterogeneity.
- The combinatorial complexity of genetic changes can lead to a near-infinite number of unique genotypes.
- Understanding these diverse genotypes is crucial for disease research, including bipolar disorder.
Related Concept Videos
01:27Principles of Pharmacogenetics: Types of Genetic Variants
The human genome is over 99.9% identical between individuals, yet genetic differences exist at millions of bases. The human genome contains approximately 3 million variant positions per individual, many of which are heterozygous, contributing to genetic diversity and individual traits. Genetic variations include single-nucleotide polymorphisms (SNPs), insertions, deletions, and copy number variations (CNVs).SNPs, the most common variation, involve single-base changes in DNA. These can be...
01:25Genetic Variation
Genetic variation is the diversity in DNA sequences found among individuals of the same species. This diversity is crucial for a species' survival because it helps organisms adapt to environmental changes. Genetic variation begins with fertilization, where an egg and sperm cell merge. Each of these cells carries 23 chromosomes, up to 46 in the fertilized egg. Chromosomes are long DNA strands that contain genes, the basic units of heredity.
Genes exist in different versions called alleles, which...
Genes exist in different versions called alleles, which...
01:28Human Genetics
Human genetics provides a profound framework for understanding the interplay between genetic predispositions and human psychology. At the heart of this discipline lies the study of how genes influence physical traits, behaviors, and susceptibility to diseases. Each person carries a unique genetic code that subtly or significantly shapes their psychological and behavioral landscape.
The complex relationship between genetics and psychology is observable through common biological components such...
The complex relationship between genetics and psychology is observable through common biological components such...
01:29Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Genetic variations significantly influence drug response through pharmacokinetics, receptor interactions, and biologic milieu modifications. Pharmacokinetic alterations impact drug metabolism and clearance, affecting efficacy and toxicity. Variants in drug-metabolizing enzymes, such as CYP2C9 and CYP2C19, alter drug activation and elimination. For example, CYP2C9 loss-of-function variants require lower warfarin doses to prevent excessive bleeding, while CYP2C19 variants reduce clopidogrel...
01:43Incomplete Dominance
Gregor Mendel's work (1822 - 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid cell has two variants called alleles inherited from each parent. He suggested that amongst these two alleles, one allele is dominant in character and the other recessive. The combination of alleles determines the phenotype of a gene in an organism.
01:11Genome-wide Association Studies-GWAS
Genome-wide association studies or GWAS are used to identify whether common SNPs are associated with certain diseases. Suppose specific SNPs are more frequently observed in individuals with a particular disease than those without the disease. In that case, those SNPs are said to be associated with the disease. Chi-square analysis is performed to check the probability of the allele likely to be associated with the disease.
GWAS does not require the identification of the target gene involved in...
GWAS does not require the identification of the target gene involved in...