Family aggregation, also known as familial aggregation, is the clustering of certain traits, behaviours, or disorders within a given family. Family aggregation may arise because of genetic or environmental similarities. [1]
The data from the family aggregation studies have been extensively studied to determine the mode of inheritance of schizophrenia. Studies to date have shown that when numerous families are studied, simple modes of inheritance are not statistically supported. The majority of studies analyzing for the mode of inheritance have concluded that a multifactorial threshold mode is most likely. [2]
The most consistent and dramatic evidence of family influences on cardiovascular disease (CVD) is family aggregation of physiological factors. In several studies the parent-child and sibling-sibling correlations of blood pressure are approximately .24. Genetic determination of blood pressure is strong, but does not explain all of the variance. [3]
Familial Parkinson's disease (PD) exists but is infrequent. Early investigations failed to show substantial family aggregation for PD. [4]
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome. The mutation responsible can occur spontaneously before embryonic development, or it can be inherited from two parents who are carriers of a faulty gene or from a parent with the disorder. When the genetic disorder is inherited from one or both parents, it is also classified as a hereditary disease. Some disorders are caused by a mutation on the X chromosome and have X-linked inheritance. Very few disorders are inherited on the Y chromosome or mitochondrial DNA.
Incest is human sexual activity between family members or close relatives. This typically includes sexual activity between people in consanguinity, and sometimes those related by lineage. It is forbidden and considered immoral in most societies, and can lead to an increased risk of genetic disorders in children in case of pregnancy.
Huntington's disease (HD), also known as Huntington's chorea, is an incurable neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental/psychiatric abilities. A general lack of coordination and an unsteady gait often follow. It is also a basal ganglia disease causing a hyperkinetic movement disorder known as chorea. As the disease advances, uncoordinated, involuntary body movements of chorea become more apparent. Physical abilities gradually worsen until coordinated movement becomes difficult and the person is unable to talk. Mental abilities generally decline into dementia, depression, apathy, and impulsivity at times. The specific symptoms vary somewhat between people. Symptoms usually begin between 30 and 50 years of age, and can start at any age but are usually seen around the age of 40. The disease may develop earlier in each successive generation. About eight percent of cases start before the age of 20 years, and are known as juvenile HD, which typically present with the slow movement symptoms of Parkinson's disease rather than those of chorea.
Sex differences in medicine include sex-specific diseases or conditions which occur only in people of one sex due to underlying biological factors ; sex-related diseases, which are diseases that are more common to one sex ; and diseases which occur at similar rates in males and females but manifest differently according to sex.
Schizoid personality disorder is a personality disorder characterized by a lack of interest in social relationships, a tendency toward a solitary or sheltered lifestyle, secretiveness, emotional coldness, detachment, and apathy. Affected individuals may be unable to form intimate attachments to others and simultaneously possess a rich and elaborate but exclusively internal fantasy world. Other associated features include stilted speech, a lack of deriving enjoyment from most activities, feeling as though one is an "observer" rather than a participant in life, an inability to tolerate emotional expectations of others, apparent indifference when praised or criticized, a degree of asexuality, and idiosyncratic moral or political beliefs.
Genetic counseling is the process of investigating individuals and families affected by or at risk of genetic disorders to help them understand and adapt to the medical, psychological and familial implications of genetic contributions to disease. This field is considered necessary for the implementation of genomic medicine. The process integrates:
Consanguinity is the characteristic of having a kinship with a relative who is descended from a common ancestor.
Essential hypertension is a form of hypertension without an identifiable physiologic cause. It is the most common type affecting 85% of those with high blood pressure. The remaining 15% is accounted for by various causes of secondary hypertension. Essential hypertension tends to be familial and is likely to be the consequence of an interaction between environmental and genetic factors. Hypertension can increase the risk of cerebral, cardiac, and renal events.
Human behaviour genetics is an interdisciplinary subfield of behaviour genetics that studies the role of genetic and environmental influences on human behaviour. Classically, human behavioural geneticists have studied the inheritance of behavioural traits. The field was originally focused on determining the importance of genetic influences on human behaviour. It has evolved to address more complex questions such as: how important are genetic and/or environmental influences on various human behavioural traits; to what extent do the same genetic and/or environmental influences impact the overlap between human behavioural traits; how do genetic and/or environmental influences on behaviour change across development; and what environmental factors moderate the importance of genetic effects on human behaviour. The field is interdisciplinary, and draws from genetics, psychology, and statistics. Most recently, the field has moved into the area of statistical genetics, with many behavioural geneticists also involved in efforts to identify the specific genes involved in human behaviour, and to understand how the effects associated with these genes changes across time, and in conjunction with the environment.
Severe congenital neutropenia (SCN), also often known as Kostmann syndrome or disease, is a group of rare disorders that affect myelopoiesis, causing a congenital form of neutropenia, usually without other physical malformations. SCN manifests in infancy with life-threatening bacterial infections. It causes severe pyogenic infections. It can be caused by autosomal dominant inheritance of the ELANE gene, autosomal recessive inheritance of the HAX1 gene. There is an increased risk of leukemia and myelodysplastic cancers.
Neuroacanthocytosis is a label applied to several genetic neurological conditions in which the blood contains misshapen, spiculated red blood cells called acanthocytes.
Psychiatric genetics is a subfield of behavioral neurogenetics and behavioral genetics which studies the role of genetics in the development of mental disorders. The basic principle behind psychiatric genetics is that genetic polymorphisms are part of the causation of psychiatric disorders.
Familial hypercholesterolemia (FH) is a genetic disorder characterized by high cholesterol levels, specifically very high levels of low-density lipoprotein cholesterol, in the blood and early cardiovascular diseases. The most common mutations diminish the number of functional LDL receptors in the liver or produce abnormal LDL receptors that never go to the cell surface to function properly. Since the underlying body biochemistry is slightly different in individuals with FH, their high cholesterol levels are less responsive to the kinds of cholesterol control methods which are usually more effective in people without FH. Nevertheless, treatment is usually effective.
Genetic epidemiology is the study of the role of genetic factors in determining health and disease in families and in populations, and the interplay of such genetic factors with environmental factors. Genetic epidemiology seeks to derive a statistical and quantitative analysis of how genetics work in large groups.
Parkinson's disease (PD), or simply Parkinson's, is a long-term neurodegenerative disease of mainly the central nervous system that affects both the motor and non-motor systems of the body. The symptoms usually emerge slowly, and as the disease progresses, non-motor symptoms become more common. Usual symptoms include tremors, slowness of movement, rigidity, and difficulty with balance, collectively known as parkinsonism. Parkinson's disease dementia, falls and neuropsychiatric problems such as sleep abnormalities, psychosis, mood swings, or behavioral changes may arise in advanced stages as well.
Behavioural genetics, also referred to as behaviour genetics, is a field of scientific research that uses genetic methods to investigate the nature and origins of individual differences in behaviour. While the name "behavioural genetics" connotes a focus on genetic influences, the field broadly investigates the extent to which genetic and environmental factors influence individual differences, and the development of research designs that can remove the confounding of genes and environment. Behavioural genetics was founded as a scientific discipline by Francis Galton in the late 19th century, only to be discredited through association with eugenics movements before and during World War II. In the latter half of the 20th century, the field saw renewed prominence with research on inheritance of behaviour and mental illness in humans, as well as research on genetically informative model organisms through selective breeding and crosses. In the late 20th and early 21st centuries, technological advances in molecular genetics made it possible to measure and modify the genome directly. This led to major advances in model organism research and in human studies, leading to new scientific discoveries.
The medical genetics of Jews have been studied to identify and prevent some rare genetic diseases that, while still rare, are more common than average among people of Jewish descent. There are several autosomal recessive genetic disorders that are more common than average in ethnically Jewish populations, particularly Ashkenazi Jews, because of relatively recent population bottlenecks and because of consanguineous marriage. These two phenomena reduce genetic diversity and raise the chance that two parents will carry a mutation in the same gene and pass on both mutations to a child.
Parkinson's disease (PD) is a complicated neurodegenerative disease that progresses over time and is marked by bradykinesia, tremor, and stiffness. As the condition worsens, some patients may also experience postural instability. Parkinson's disease (PD) is primarily caused by the gradual degeneration of dopaminergic neurons in the region known as the substantia nigra along with other monoaminergic cell groups throughout the brainstem, increased activation of microglia, and the build-up of Lewy bodies and Lewy neurites, which are proteins found in surviving dopaminergic neurons.
Alice M. Lazzarini is a scientist, author and researcher on neurogenetic disorders, including Huntington's disease and Parkinson's disease. She is an assistant professor of Neurology at Rutgers Robert Wood Johnson Medical School, where her work helped establish the genetic basis of Parkinson's. Later in life, she was diagnosed with Parkinson's—the very disease she had spent decades researching.
Animal models of Parkinson's disease are essential in the research field and widely used to study Parkinson's disease. Parkinson's disease is a neurodegenerative disorder, characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The loss of the dopamine neurons in the brain, results in motor dysfunction, ultimately causing the four cardinal symptoms of PD: tremor, rigidity, postural instability, and bradykinesia. It is the second most prevalent neurodegenerative disease, following Alzheimer's disease. It is estimated that nearly one million people could be living with PD in the United States.