Medical genetics is the branch of medicine that involves the diagnosis and management of hereditary disorders. Medical genetics differs from human genetics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the causes and inheritance of genetic disorders would be considered within both human genetics and medical genetics, while the diagnosis, management, and counselling people with genetic disorders would be considered part of medical genetics.

In contrast, the study of typically non-medical phenotypes such as the genetics of eye color would be considered part of human genetics, but not necessarily relevant to medical genetics (except in situations such as albinism). Genetic medicine is a newer term for medical genetics and incorporates areas such as gene therapy, personalized medicine, and the rapidly emerging new medical specialty, predictive medicine.

Medical genetics encompasses many different areas, including clinical practice of physicians, genetic counselors, and nutritionists, clinical diagnostic laboratory activities, and research into the causes and ixxxxxx nheritance of genetic disorders. Examples of conditions that fall within the scope of medical genetics include birth defects and dysmorphology, mental retardation, autism, and mitochondrial disorders, skeletal dysplasia, connective tissue disorders, cancer genetics, teratogens, and prenatal diagnosis. Medical genetics is increasingly becoming relevant to many common diseases. Overlaps with other medical specialties are beginning to emerge, as recent advances in genetics are revealing etiologies for neurologic, endocrine, cardiovascular, pulmonary, ophthalmologic, renal, psychiatric, and dermatologic conditions.

In some ways, many of the individual fields within medical genetics are hybrids between clinical care and research. This is due in part to recent advances in science and technology (for example, see the Human genome project) that have enabled an unprecedented understanding of genetic disorders.

Clinical genetics is the practice of clinical medicine with particular attention to hereditary disorders. Referrals are made to genetics clinics for a variety of reasons, including birth defects, developmental delay, autism, epilepsy, short stature, and many others. Examples of genetic syndromes that are commonly seen in the genetics clinic include chromosomal rearrangements, Down syndrome, DiGeorge syndrome (22q11.2 Deletion Syndrome), Fragile X syndrome, Marfan syndrome, Neurofibromatosis, Turner syndrome, and Williams syndrome.

In the United States, physicians who practice clinical genetics are accredited by the American Board of Medical Genetics and Genomics (ABMGG).[1] In order to become a board-certified practitioner of Clinical Genetics, a physician must complete a minimum of 24 months of training in a program accredited by the ABMGG. Individuals seeking acceptance into clinical genetics training programs must hold an M.D. or D.O. degree (or their equivalent) and have completed a minimum of 24 months of training in an ACGME-accredited residency program in internal medicine, pediatrics, obstetrics and gynecology, or other medical specialty.[2]

Metabolic (or biochemical) genetics involves the diagnosis and management of inborn errors of metabolism in which patients have enzymatic deficiencies that perturb biochemical pathways involved in metabolism of carbohydrates, amino acids, and lipids. Examples of metabolic disorders include galactosemia, glycogen storage disease, lysosomal storage disorders, metabolic acidosis, peroxisomal disorders, phenylketonuria, and urea cycle disorders.

Cytogenetics is the study of chromosomes and chromosome abnormalities. While cytogenetics historically relied on microscopy to analyze chromosomes, new molecular technologies such as array comparative genomic hybridization are now becoming widely used. Examples of chromosome abnormalities include aneuploidy, chromosomal rearrangements, and genomic deletion/duplication disorders.

Molecular genetics involves the discovery of and laboratory testing for DNA mutations that underlie many single gene disorders. Examples of single gene disorders include achondroplasia, cystic fibrosis, Duchenne muscular dystrophy, hereditary breast cancer (BRCA1/2), Huntington disease, Marfan syndrome, Noonan syndrome, and Rett syndrome. Molecular tests are also used in the diagnosis of syndromes involving epigenetic abnormalities, such as Angelman syndrome, Beckwith-Wiedemann syndrome, Prader-willi syndrome, and uniparental disomy.

Mitochondrial genetics concerns the diagnosis and management of mitochondrial disorders, which have a molecular basis but often result in biochemical abnormalities due to deficient energy production.

There exists some overlap between medical genetic diagnostic laboratories and molecular pathology.

Genetic counseling is the process of providing information about genetic conditions, diagnostic testing, and risks in other family members, within the framework of nondirective counseling. Genetic counselors are non-physician members of the medical genetics team who specialize in family risk assessment and counseling of patients regarding genetic disorders. The precise role of the genetic counselor varies somewhat depending on the disorder.

Although genetics has its roots back in the 19th century with the work of the Bohemian monk Gregor Mendel and other pioneering scientists, human genetics emerged later. It started to develop, albeit slowly, during the first half of the 20th century. Mendelian (single-gene) inheritance was studied in a number of important disorders such as albinism, brachydactyly (short fingers and toes), and hemophilia. Mathematical approaches were also devised and applied to human genetics. Population genetics was created.

Medical genetics was a late developer, emerging largely after the close of World War II (1945) when the eugenics movement had fallen into disrepute. The Nazi misuse of eugenics sounded its death knell. Shorn of eugenics, a scientific approach could be used and was applied to human and medical genetics. Medical genetics saw an increasingly rapid rise in the second half of the 20th century and continues in the 21st century.

The clinical setting in which patients are evaluated determines the scope of practice, diagnostic, and therapeutic interventions. For the purposes of general discussion, the typical encounters between patients and genetic practitioners may involve:

Each patient will undergo a diagnostic evaluation tailored to their own particular presenting signs and symptoms. The geneticist will establish a differential diagnosis and recommend appropriate testing. Increasingly, clinicians use SimulConsult, paired with the National Library of Medicine Gene Review articles, to narrow the list of hypotheses (known as the differential diagnosis) and identify the tests that are relevant for a particular patient. These tests might evaluate for chromosomal disorders, inborn errors of metabolism, or single gene disorders.

Chromosome studies are used in the general genetics clinic to determine a cause for developmental delay/mental retardation, birth defects, dysmorphic features, and/or autism. Chromosome analysis is also performed in the prenatal setting to determine whether a fetus is affected with aneuploidy or other chromosome rearrangements. Finally, chromosome abnormalities are often detected in cancer samples. A large number of different methods have been developed for chromosome analysis:

Biochemical studies are performed to screen for imbalances of metabolites in the bodily fluid, usually the blood (plasma/serum) or urine, but also in cerebrospinal fluid (CSF). Specific tests of enzyme function (either in leukocytes, skin fibroblasts, liver, or muscle) are also employed under certain circumstances. In the US, the newborn screen incorporates biochemical tests to screen for treatable conditions such as galactosemia and phenylketonuria (PKU). Patients suspected to have a metabolic condition might undergo the following tests:

Each cell of the body contains the hereditary information (DNA) wrapped up in structures called chromosomes. Since genetic syndromes are typically the result of alterations of the chromosomes or genes, there is no treatment currently available that can correct the genetic alterations in every cell of the body. Therefore, there is currently no "cure" for genetic disorders. However, for many genetic syndromes there is treatment available to manage the symptoms. In some cases, particularly inborn errors of metabolism, the mechanism of disease is well understood and offers the potential for dietary and medical management to prevent or reduce the long-term complications. In other cases, infusion therapy is used to replace the missing enzyme. Current research is actively seeking to use gene therapy or other new medications to treat specific genetic disorders.

In general, metabolic disorders arise from enzyme deficiencies that disrupt normal metabolic pathways. For instance, in the hypothetical example:

Compound "A" is metabolized to "B" by enzyme "X", compound "B" is metabolized to "C" by enzyme "Y", and compound "C" is metabolized to "D" by enzyme "Z". If enzyme "Z" is missing, compound "D" will be missing, while compounds "A", "B", and "C" will build up. The pathogenesis of this particular condition could result from lack of compound "D", if it is critical for some cellular function, or from toxicity due to excess "A", "B", and/or "C". Treatment of the metabolic disorder could be achieved through dietary supplementation of compound "D" and dietary restriction of compounds "A", "B", and/or "C" or by treatment with a medication that promoted disposal of excess "A", "B", or "C". Another approach that can be taken is enzyme replacement therapy, in which a patient is given an infusion of the missing enzyme.

Dietary restriction and supplementation are key measures taken in several well-known metabolic disorders, including galactosemia, phenylketonuria (PKU), maple syrup urine disease, organic acidurias and urea cycle disorders. Such restrictive diets can be difficult for the patient and family to maintain, and require close consultation with a nutritionist who has special experience in metabolic disorders. The composition of the diet will change depending on the caloric needs of the growing child and special attention is needed during a pregnancy if a woman is affected with one of these disorders.

Medical approaches include enhancement of residual enzyme activity (in cases where the enzyme is made but is not functioning properly), inhibition of other enzymes in the biochemical pathway to prevent buildup of a toxic compound, or diversion of a toxic compound to another form that can be excreted. Examples include the use of high doses of pyridoxine (vitamin B6) in some patients with homocystinuria to boost the activity of the residual cystathione synthase enzyme, administration of biotin to restore activity of several enzymes affected by deficiency of biotinidase, treatment with NTBC in Tyrosinemia to inhibit the production of succinylacetone which causes liver toxicity, and the use of sodium benzoate to decrease ammonia build-up in urea cycle disorders.

Certain lysosomal storage diseases are treated with infusions of a recombinant enzyme (produced in a laboratory), which can reduce the accumulation of the compounds in various tissues. Examples include Gaucher disease, Fabry disease, Mucopolysaccharidoses and Glycogen storage disease type II. Such treatments are limited by the ability of the enzyme to reach the affected areas (the blood brain barrier prevents enzyme from reaching the brain, for example), and can sometimes be associated with allergic reactions. The long-term clinical effectiveness of enzyme replacement therapies vary widely among different disorders.

There are a variety of career paths within the field of medical genetics, and naturally the training required for each area differs considerably. It should be noted that the information included in this section applies to the typical pathways in the United States and there may be differences in other countries. US Practitioners in clinical, counseling, or diagnostic subspecialties generally obtain board certification through the American Board of Medical Genetics.

Genetic information provides a unique type of knowledge about an individual and his/her family, fundamentally different from a typically laboratory test that provides a "snapshot" of an individual's health status. The unique status of genetic information and inherited disease has a number of ramifications with regard to ethical, legal, and societal concerns.

On 19 March 2015, scientists urged a worldwide ban on clinical use of methods, particularly the use of CRISPR and zinc finger, to edit the human genome in a way that can be inherited.[3][4][5][6] In April 2015 and April 2016, Chinese researchers reported results of basic research to edit the DNA of non-viable human embryos using CRISPR.[7][8][9] In February 2016, British scientists were given permission by regulators to genetically modify human embryos by using CRISPR and related techniques on condition that the embryos were destroyed within seven days.[10] In June 2016 the Dutch government was reported to be planning to follow suit with similar regulations which would specify a 14-day limit.[11]

The more empirical approach to human and medical genetics was formalized by the founding in 1948 of the American Society of Human Genetics. The Society first began annual meetings that year (1948) and its international counterpart, the International Congress of Human Genetics, has met every 5 years since its inception in 1956. The Society publishes the American Journal of Human Genetics on a monthly basis.

Medical genetics is now recognized as a distinct medical specialty in the U.S. with its own approved board (the American Board of Medical Genetics) and clinical specialty college (the American College of Medical Genetics). The College holds an annual scientific meeting, publishes a monthly journal, Genetics in Medicine, and issues position papers and clinical practice guidelines on a variety of topics relevant to human genetics.

The broad range of research in medical genetics reflects the overall scope of this field, including basic research on genetic inheritance and the human genome, mechanisms of genetic and metabolic disorders, translational research on new treatment modalities, and the impact of genetic testing

Basic research geneticists usually undertake research in universities, biotechnology firms and research institutes.

Sometimes the link between a disease and an unusual gene variant is more subtle. The genetic architecture of common diseases is an important factor in determining the extent to which patterns of genetic variation influence group differences in health outcomes.[12][13][14] According to the common disease/common variant hypothesis, common variants present in the ancestral population before the dispersal of modern humans from Africa play an important role in human diseases.[15] Genetic variants associated with Alzheimer disease, deep venous thrombosis, Crohn disease, and type 2 diabetes appear to adhere to this model.[16] However, the generality of the model has not yet been established and, in some cases, is in doubt.[13][17][18] Some diseases, such as many common cancers, appear not to be well described by the common disease/common variant model.[19]

Another possibility is that common diseases arise in part through the action of combinations of variants that are individually rare.[20][21] Most of the disease-associated alleles discovered to date have been rare, and rare variants are more likely than common variants to be differentially distributed among groups distinguished by ancestry.[19][22] However, groups could harbor different, though perhaps overlapping, sets of rare variants, which would reduce contrasts between groups in the incidence of the disease.

The number of variants contributing to a disease and the interactions among those variants also could influence the distribution of diseases among groups. The difficulty that has been encountered in finding contributory alleles for complex diseases and in replicating positive associations suggests that many complex diseases involve numerous variants rather than a moderate number of alleles, and the influence of any given variant may depend in critical ways on the genetic and environmental background.[17][23][24][25] If many alleles are required to increase susceptibility to a disease, the odds are low that the necessary combination of alleles would become concentrated in a particular group purely through drift.[26]

One area in which population categories can be important considerations in genetics research is in controlling for confounding between population substructure, environmental exposures, and health outcomes. Association studies can produce spurious results if cases and controls have differing allele frequencies for genes that are not related to the disease being studied,[27] although the magnitude of this problem in genetic association studies is subject to debate.[28][29] Various methods have been developed to detect and account for population substructure,[30][31] but these methods can be difficult to apply in practice.[32]

Population substructure also can be used to advantage in genetic association studies. For example, populations that represent recent mixtures of geographically separated ancestral groups can exhibit longer-range linkage disequilibrium between susceptibility alleles and genetic markers than is the case for other populations.[33][34][35][36] Genetic studies can use this admixture linkage disequilibrium to search for disease alleles with fewer markers than would be needed otherwise. Association studies also can take advantage of the contrasting experiences of racial or ethnic groups, including migrant groups, to search for interactions between particular alleles and environmental factors that might influence health.[37][38]

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Medical genetics - Wikipedia

As per a new study, up to 40% of your body-mass index (BMI) may have been inherited from your parents. The report adds that nearly half of a kids tendency towards obesity is determined by genetics and family environment.

Your obesity worries you? Do you feel guilty every time you have a candy? This research should help you deal with it. A recent study says that up to 40% of your body-mass index may have been inherited from your parents. It adds that more than half of a kids tendency towards obesity is determined by genetics and family environment.

For the most obese children, the proportion rises to 55-60%, researchers said.

The study, led by the University of Sussex in the UK, used data on the heights and weights of 100,000 children and their parents spanning six countries worldwide: the UK, US, China, Indonesia, Spain and Mexico.

The researchers found that the intergenerational transmission of body-mass index (BMI) is almost constant at around 0.2 per parent -- that is each childs BMI on average is around 20% due to the mother and 20% due to the father.

The pattern of results is remarkably consistent across all countries, irrespective of their stage of economic development, degree of industrialisation, or type of economy, said Peter Dolton, Professor at the University of Sussex in the UK.

Our evidence comes from trawling data from across the world with very diverse patterns of nutrition and obesity -- from one of the most obese populations -- the US -- to two of the least obese countries in the world -- China and Indonesia.

This gives an important and rare insight into how obesity is transmitted across generations in both developed and developing countries, said Dolton.

We found that the process of intergenerational transmission is the same across all the different countries, he said.

Up to 40% of your body-mass index (BMI) comes from your parents. (Shutterstock)

The study also shows how the effect of parents BMI on their childrens BMI depends on what the BMI of the child is. Consistently, across all populations studied, they found the parental effect to be lowest for the thinnest children and highest for the most obese children.

For the thinnest child their BMI is 10% due to their mother and 10% due to their father. For the fattest child this transmission is closer to 30% due to each parent.

This shows that the children of obese parents are much more likely to be obese themselves when they grow up - the parental effect is more than double for the most obese children what it is for the thinnest children, said Dolton.

The findings were published in the journal Economics and Human Biology.

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Genetics, family set-up play a big role in your tendency to put on weight - Hindustan Times

According to an international team of researchers led by University College London and Kings College London, the discovery of a molecular switch that causes the mucosal inflammatory diseases ulcerative colitis, Crohns disease, and celiac disease, could lead to effective new treatments for these autoimmune conditions. The discovery is reported in the journal PLoS Genetics.

According to Soderquest et al, T-bet plays an important role in coordinating the bodys immune responses. Image credit: Werbe Fabrik.

For the first time, researchers have a specific target for the treatment of these life-changing conditions by identifying an immune molecule called T-bet (TBX21) as the key control point that regulates the genetic risk in specific diseases.

Our research outlines a specific focus for the development of new treatments for these diseases which have such a profound effect on sufferers, explained Kings College London Professor Graham Lord, co-senior author on the study.

In the study, Prof. Lord and his colleagues examined how genetic variation affects T-bet binding to DNA, as a key regulatory mechanism in the immune response.

Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) that may be causative for autoimmune diseases, the researchers said.

The majority of these polymorphisms are located within non-coding distal regulatory elements.

It is considered that these genetic variants contribute to disease by altering the binding of regulatory proteins and thus gene expression, but whether these variants alter the binding of lineage-specifying transcription factors has not been determined.

The researchers found that T-bet binding sites are specifically enriched in genetic variants associated with the mucosal autoinflammatory diseases.

They also identified genetic variants that alter T-bet binding and gene expression.

We show that SNPs associated with the mucosal inflammatory diseases Crohns disease, ulcerative colitis and celiac disease, but not rheumatoid arthritis or psoriasis, are enriched at T-bet binding sites, the authors said.

Furthermore, we identify disease-associated variants that alter T-bet binding in vitro and in vivo.

Our results suggest that genetic polymorphisms may predispose individuals to mucosal autoimmune disease through alterations in T-bet binding, they said.

Other disease-associated variants may similarly act by modulating the binding of lineage-specifying transcription factors in a tissue-selective and disease-specific manner.

_____

K. Soderquest et al. 2017. Genetic variants alter T-bet binding and gene expression in mucosal inflammatory disease. PLoS Genet 13 (2): e1006587; doi: 10.1371/journal.pgen.1006587

Link:
'Molecular Switch' that Causes Mucosal Autoimmune Diseases Discovered - Sci-News.com

We hear the terms genetics and genomics being used in countless scientific studies as well as more mainstream news reports. But despite the two words sounding similar, genetics and genomics refer to two very different things. Do you know the difference between these two terms? What separates genetics from genomics and vice versa? Here is how you can find out in one minute.

The GLP aggregated and excerpted this blog/article to reflect the diversity of news, opinion, and analysis. Watch the original video:What is the Difference Between Genetics and Genomics?

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Video: Understand the difference between genetics and genomics in 1 minute - Genetic Literacy Project

ALISO VIEJO, Calif.--(BUSINESS WIRE)--

Ambry Genetics (Ambry) has created an online portal to enable more patients and families to participate in research through the AmbryShare program. With this simplified portal, Ambry has streamlined the research consent process to make cohort recruitment easier for clinicians at the time of sample collection for clinical testing.

Patients now have the flexibility to e-consent from home, or a mobile device during their office visits. An individual can also enroll themselves and submit a sample to the program independently, whether or not their clinician orders a clinical test at Ambry.

The new e-consent portal is one more example of the companys mission to use AmbryShare to remove the red-tape that has been slowing down scientific progress.

The data-sharing program is currently focused on the genomics of autism and prostate cancer, and Ambry is actively seeking research partners for those initiatives.

We've created a simple way for patients to participate in crowd-sourced research, said Brigette Tippin Davis, PhD, Ambrys Director of Emerging Genetic Medicine. If your family is impacted by disease, we are empowering you to make a real difference. AmbryShare freely enables researchers worldwide to put your de-identified genomic DNA to work to find treatments, keeping your privacy protected at the same time.

Since March 2016, Ambry has provided researchers with de-identified aggregated data from whole exome sequencing on a large cohort of affected patients with the intention of aiding and accelerating scientific research at no cost to the public. This data will ultimately help clinicians create more tailored treatments through enhanced understanding of human disease.

For more information and to enroll in AmbryShare, visit the AmbryShare portal here.

ABOUT AMBRY GENETICS

Ambry Genetics is both College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified. Ambry leads in clinical genetic diagnostics and genetics software solutions, combining both to offer the most comprehensive testing menu in the industry. Ambry has established a reputation for sharing data while safeguarding patient privacy, unparalleled service, and responsibly applying new technologies to the clinical molecular diagnostics market. For more information about Ambry Genetics, visit http://www.ambrygen.com.

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Ambry Genetics Launches New Site for Cohort Recruitment - Yahoo Finance

LUMBERTON

The first national health conference of its kind is coming to Southeast Texas this weekend.

On Saturday, the Pathway to Freedom Health Conference will focus on natural health and wellness.

There will be multiple speakers on topics from basic nutrition and natural health support to spirituality, genetics and functional health.

Attendees can also shop with different vendors. Tickets are $37 and details can be found by clicking this link.

The conference is scheduled from 9 a.m. to 5 p.m. at the Lumberton ISD Performing Arts Center (103 South LHS Drive in Lumberton). Doors open at 8 a.m.

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Lumberton health conference to focus on nutrition, genetics - KBTV Fox 4 Beaumont

Scientists at the University of British Columbia have genetically engineered a mouse that does not become addicted to cocaine, adding to the evidence that habitual drug use is more a matter of genetics and biochemistry than just poor judgment.

The mice they created had higher levels of a protein called cadherin, whichhelps strengthen synapses between neurons.

[After injecting cocaine into mice, researchers found that]the normal mice almost always gravitated to the cocaine-associated compartment, while the mice with extra cadherin spent half as much time there indicating that these mice hadnt formed strong memories of the drug.

By preventing the synapses from strengthening, we prevented the mutant mice from learning the memory of cocaine, and thus prevented them from becoming addicted,says graduate student and co-author Andrea Globa.

A diagram showing synapses in the reward circuit of mice when exposed to cocaine: on left, a normal mouse, and on right, a mouse with increased levels of cadherin. Credit: University of British Columbia.

Their finding provides an explanation for previous studies showing that people with substance use problems tend to have more genetic mutations associated with cadherin and cell adhesion. As studies such as this one illuminate the biochemical underpinnings of addiction, it could lead to greater confidence in predicting who is more vulnerable to drug abuse and enable people to act on that knowledge.

[The study can be found here.]

The GLP aggregated and excerpted this blog/article to reflect the diversity of news, opinion, and analysis. Read full, original post:Scientists create mouse that resists cocaines lure

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Drug addiction may be fueled by genetics, not just poor judgment - Genetic Literacy Project