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Clinical Geneticist

Clinical Geneticist

Medical genetics is the application of genetics to the study of human health and diseases. As a profession, medical genetics is usually a mixture of both clinical services and research. Worldwide, services can include diagnosis, counseling, and management of birth defects and genetic disorders. How medical genetics is actually practiced depends on several factors, including the expertise and training of the professionals involved, the expertise available within any given medical facility, and the structure of the practice of medicine within a given society.

In the United States, the practice of medical genetics includes two different career tracks, both requiring certification by the American Board of Medical Genetics (ABMG): the medical geneticist and the clinical geneticist. A medical geneticist holds a Ph.D. and is certified in medical genetics. Typically a medical geneticist is a highly trained research laboratory professional who can additionally take on the role of consultant to physicians. A clinical geneticist is a physician (either a doctor of osteopathy or a medical doctor) involved in all parts of clinical practice related to genetic disorders. Working closely with patients, clinical geneticists identify, diagnose, determine the prognosis of, develop predictive tests for, treat, and manage genetic diseases. They can also be active in conducting research on genetic disorders and studying theoretical genetics, and they usually help to administer and set policies for the clinical genetics profession and for medical centers in general.

Clinical geneticists also can be involved in the bioethical debates and policy-making issues concerning how genetic information is gathered, who has access to it, and how that access should be regulated. This role is becoming increasingly important as society struggles to deal with the tremendous explosion of genetic information arising as a consequence of the Human Genome Project. Administrative roles for clinical geneticists can include formulating plans and procedures for clinical genetic services, scheduling the use of medical genetics facilities, and teaching interns and residents the methods and procedures involved in the diagnosis and management of genetic disorders.

Very few clinical geneticists develop a private practice. Instead, they typically work in a team environment within regional medical centers alongside scientists, medical geneticists, genetic counselors, and other academics. Most hospitals specializing in pediatric care will also have clinical geneticists on their staff. Some large national clinics have entire departments devoted to the practice of medical and clinical genetics.

Physicians are attracted to the practice of clinical genetics for a variety of reasons. Many enjoy understanding the evolving human gene map, the rapid technological advances in the field, and the opportunity to perform laboratory research as well as practice medicine. They enjoy the challenge of applying the advances in the molecular basis of disease to the care of patients. As a group, clinical geneticists derive satisfaction by remaining close to the "cutting edge" of new discoveries in genetic diseases, which challenges them to remain current while constantly using their knowledge and skills to provide innovative and effective medical services.

Many are attracted to the profession because it allows them to develop long-term relationships with patients and their families. Others find that the narrow focus of clinical genetics is more to their liking than the broader disciplines of internal medicine or pediatrics. Within clinical genetics, physicians can develop their own disease specialty if they choose, which for some provides a more rewarding work environment, giving them the opportunity to make an impact on both research and the lives of patients whose diseases may be rare and often poorly understood by other medical practitioners. Clinical geneticists enjoy complex problem-solving, taking care of people, and paying attention to details that others may miss. They are good listeners.

Students interested in clinical genetics as a profession should become familiar with mathematics, chemistry, biology, and some physics, while still in high school. Courses aimed at developing communication and writing skills are also valuable for students preparing for a career in clinical genetics. Because the practice of clinical genetics requires a medical degree, students must first receive a bachelor's degree, enrolling in courses that meet medical school admission requirements.

After obtaining a medical degree, clinical geneticists typically complete three to five years of residency in medical disciplines approved by the Accreditation Council for Graduate Medical Education (ACGME), followed by a two-to three-year fellowship that is approved by the ABMG, in clinical genetics itself. Certification can be in clinical genetics or in more focused subspecialties, including clinical cytogenetics, clinical biochemical genetics, clinical molecular genetics, and molecular genetic pathology. Certification requires the successful passage of a national examination that is given at regularly scheduled intervals. To maintain certification, clinical geneticists must fulfill continuing education requirements throughout the duration of their career.

Both the ACGME and ABMG maintain a list of approved programs that lead to certification as a clinical geneticist. Approved residency programs include clinical and academic components. Approved programs expose the resident to a patient population large enough to develop an understanding of the wide variety of medical genetic problems. They enable direct involvement in genetic research laboratories, where students learn to critically interpret laboratory data. They include graduate-level course work in basic, human, and medical genetics, as well as clinical teaching conferences, and they foster the development of the communication skills necessary to interact and sustain a long-term therapeutic relationship with patients and their families.

One need not necessarily decide upon the profession of clinical genetics prior to entering medical school or even upon receiving a medical degree or completing a full residency. Traditionally, the ABMG has accepted physicians into clinical genetics programs who come from approved residency programs in pediatrics, obstetrics-gynecology, and internal medicine. This is because the profession of clinical genetics originated from the treatment of inherited diseases that are initially observed in newborn infants and children. It is still within these disciplines that many physicians develop a secondary interest in clinical genetics, during residency or even later in their medical career. However, the field of medical genetics is rapidly changing, due to the recognition that many genetic disorders result in symptoms that are delayed until adulthood. As a consequence, clinical geneticists are now beginning to provide their services to adults as well.

The Human Genome Project has also brought the realization that clinical genetics involves more than single-gene and single-chromosome conditions. Genetic medicine is becoming applicable to many kinds of complex diseases and disorders such as cancer, heart disease, and asthma, to name a few well-known conditions.

The 1,100 certified clinical geneticists registered in the United States in the year 2000 were too few to keep up with an ever-increasing demand for their services. Students interested in pursuing clinical genetic careers can expect that the number of subspecialties will continue to grow, that both the ACGME and ABMG will continue to strive to provide new certification programs and career tracks, and that the concept of clinical genetics may become an integral component of "well" medical health care.

see also Disease, Genetics of; Genetic Counselor; Genetic Testing; Genetic Testing: Ethical Issues; Prenatal Diagnosis.

Diane C. Rein


Internet Resources

Accreditation Council for Graduate Medical Education. <>.

American Board of Medical Genetics. <>.

Careers in Human Genetics. University of Kansas Medical Center's Genetics Education Center. <>.

Guide to North American Graduate and Postgraduate Training Programs in Human Genetics. American Board of Medical Genetics. <>.

National Coalition for Health Professional Education in Genetics. <>.

Webliography for Clinical Geneticists. The Federation of American Societies for Experimental Biology. <>.

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Microbiology, Clinical

microbiology, Clinical

Clinical microbiology is concerned with infectious microorganisms . Various bacteria , algae and fungi are capable of causing disease.

Disease causing microorganisms have been present for millennia. Examples include anthrax , smallpox , bacterial tuberculosis , plague, diphtheria , typhoid fever , bacterial diarrhea, and pneumonia . While modern technological advances, such as mass vaccination , have reduced the threat of some of these diseases, others remain a problem. Some illnesses are reemerging, due to acquisition of resistance to many antibiotics . Finally, other diseases, such as the often lethal hemorrhagic fever caused by the Ebola virus , have only been recognized within the past few decades.

Many bacterial diseases have only been recognized since the 1970s. These include Legionnaires' disease , Campylobacter infection of poultry, toxic shock syndrome , hemolytic uremic syndrome, Lyme disease , peptic ulcer disease, human ehrlichiosis, and a new strain of cholera. Clinical microbiology research and techniques were vital in identifying the cause of these maladies, and in seeking treatments and ultimately a cure for each malady.

Clinical microbiology involves both the detection and identification of disease-causing microorganisms, and research to find more effective means of treating the infection or preventing infections from occurring. The symptoms of the ailment, and the shape, Gram stain reaction (in the case of bacteria), and biochemical reactions of an unknown organism are used to diagnose the cause of an infection. Knowledge of the identity of the microbe suggests means of treatment, such as the application of antibiotics. Many clinical microbiologists are also researchers. In many cases, the molecular basis of an organism's disease-causing capability is not clear. Unraveling the reasons why a disease is produced can help find ways to prevent the disease.

There are several groups or categories of bacteria that are of medical importance. They are grouped into five categories based on their shape and reaction to the Gram stain. These criteria apply to the light microscope , as typically a first step in the identification of bacteria in an infection is the light microscope examination of material obtained from the infection or from a culture . The groups are Gram-positive bacilli (rod-shaped bacteria), Gram negative bacilli, Gram positive cocci (round bacteria), Gram negative cocci, and bacteria that react atypically to the Gram stain.

A group of spiral shaped bacteria called spirochetes are responsible for leptospirosis in dogs, and syphilis and Lyme disease in humans. These bacteria are easily identified under the light microscope because of their wavy shape and corkscrew movement (courtesy of rigid internal filaments that run the length of the bacterium). A related group (a genus) of spiral shaped bacteria is Spirilla. These bacteria move by means of external flagella, not by means of the internal filaments. Two members of Spirilla are important disease-causing bacteria. The first is Campylobacter jejuni, which frequently contaminates raw meat such as poultry and drinking water, and which is the cause of diarrhea, especially in children. The second bacterial type is Helicobacter pylori, which grows in the stomach and has been demonstrated to be the principle cause of stomach ulcers.

Another group of clinically relevant bacteria is termed pseudomonads. This group contains many different types of bacteria. They all are similar in shape and biochemical behavior to a species called Pseudomonas aeruginosa. Most pseudomonads, like Pseudomonas aeruginosa live in water and the soil. They cause a variety of ailments. Bordetella pertussis causes whooping cough, Legionella pneumophila causes Legionnaires' disease, Neisseria gonorrhoeae causes gonorrhea , and Neisseria meningitides causes bacterial meningitis . Pseudomonas aeruginosa is the quintessential so-called opportunitistic pathogen; a bacteria that does not normally cause an infection but can do so in a compromised host. Examples of such infections are the chronic lung infections in those who have certain forms of cystic fibrosis, and infections in burn victims.

Yet another group of bacteria of medical importance live in the intestinal tracts of humans, other mammals and even in birds and reptiles. These are the enteric bacteria. The best-known enteric bacteria is Escherichia coli , the cause of intestinal illness and sometimes even more severe damage to the urinary tract and kidneys from ingestion of contaminated water or food ("hamburger disease"). Other noteworthy enteric bacteria are Shigella dysenteriae (dysentery ), Salmonella species gastroenteritis and typhoid fever), Yersinia pestis (bubonic plague ), and Vibrio cholerae (cholera).

Bacteria including Staphylococcus and Streptococcus, which normally live on the skin, can cause infection when they gain entry to other pasts of the body. The illnesses they cause (such as strep throat , pneumonia, and blood infection, as examples), and the number of cases of these illnesses, make them the most clinically important disease-causing bacteria known to man. Staphylococcus aureus is the leading cause of hospital acquired infections of all the gram-positive bacteria. Ominously, a strain of this organism now exists that is resistant to many antibiotics. As this strain increases its worldwide distribution, Staphylococcus infections will become an increasing problem.

Bacteria that normally live in the mouth are responsible for the formation of dental plaque on the surface of teeth. Protected within the plaque, the bacteria produce acid that eats away tooth enamel, leading to the development of a cavity.

A few examples of other clinically important bacteria are Bacillus anthracis (anthrax), Clostridium tetani (tetanus ), Mycobacterium tuberculosis (tuberculosis), Corynebacterium diphtheriae (diphtheria), various Rickettsias (Rocky Mountain Spotted Fever, Q fever ), Chlamydia trachomatis (chlamydia).

Fungi and yeast are also capable of causing infection. For example, the fungal genus Tinea comprises species that cause conditions commonly described as "jock itch" and "athlete's foot." Scalp infections are also caused by some species of fungus.

Viruses are also the cause of a variety of infections. Inflammation of the coating of nerve cells (meningitis) and brain tissue (encephalitis), and infections of tissues in the mouth, bronchial tract, lungs and intestinal tract result from infection by various viruses.

See also Blood borne infections; Cold, viruses; Laboratory techniques in microbiology; Viruses and response to viral infection; Yeast, infectious

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Clinical Assessment Scales for the Elderly

Clinical Assessment Scales for the Elderly


The Clinical Assessment Scales for the Elderly, often abbreviated as CASE, is a diagnostic tool used to deter mine the presence of mental disorders and other conditions in elderly adults.


The CASE is used to determine the presence of mental disorders in an elderly person as defined by the Diagnostic and Statistical Manual of Mental Disorders , fourth edition, text revision (2000), which is also called DSM-IV-TR. The DSM-IV-TR is the basic reference work consulted by mental health professionals when making a diagnosis . The CASE, which is used with adults between the ages of 55 and 90, consists of a self-report form in which the person answers questions about himself or herself related to various scales. If the elderly adult is unable to complete the form because of cognitive or physical deficiencies, an other-rating form is provided for use by a knowledgeable caregiver, such as a spouse, child, or health care worker.

The CASE is not always used specifically for diagnosing mental disorders. It may be administered simply as a general assessment tool to gain insight about an elderly person. It may serve as a neurological screening tool to rule out other problems. The test makers also claim that it can be used as an early screening tool for dementia and thus allow elderly adults to receive medications to slow the progress of Alzheimer's disease .


The Clinical Assessment Scales for the Elderly were written by Cecil Reynolds and Erin Bigler. The most recent version of the test was published in 2001. The CASE consists of 10 clinical scales that measure the following: Anxiety; Cognitive Competence; Depression; Fear of Aging; Obsessive-Compulsiveness; Paranoia ; Psychoticism; Somatization; Mania; and Substance Abuse. The degree to which an elderly person exhibits symptoms in these areas can help a mental health professional with the process of differential diagnosis for a mental disorder.

The CASE also includes three validity scales. These are helpful in evaluating the consistency of a person's responses and whether the person is faking his or her answers.

The person who is completing the CASE, whether they are using the self-rating or the other-rating form, responds to the test's written items. The test usually takes between 2040 minutes to finish, but it is not timed. People are generally given as much time as they need to complete it.

A shorter version of the test, called the Clinical Assessment Scales for the Elderly-Short Form (CASESF) is also available. The CASE-SF takes about 20 minutes to complete and includes all 10 of the clinical scales.


Scoring for the CASE is relatively simple. Scores are calculated for each scale and then compared to age-appropriate scores to determine the presence or severity of symptoms. For example, if a person scores high on the Depression scale, this information could be used as part of an overall diagnosis for a DSM-IV depressive disorder. A person scoring high in Psychoticism may have a psychotic disorder. For any specific DSM-IV diagnosis to be made, however, all of the required criteria for that disorder must be met. The results from the CASE may satisfy only some of the requirements.

The Fear of Aging scale assesses the person's degree of apprehension or concern about the aging process. It is not necessarily related to a particular DSM-IV disorder. Information about a person's fear of aging, however, may be helpful during the diagnostic process. It may also be useful information for a psychotherapist or other counselor, to understand the patient's concerns or to measure progress in therapy.

The CASE was standardized using a sample of 2000 adults in the United States, 1000 for each of the two test forms. The test has been shown to have good reliability and validity. For example, scores from the CASE Depression scale have been shown to correlate very well with scores on the widely used Beck Depression Inventory , or BDI.

See also Figure drawings; House-Tree-Person Test



American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th edition, text revised. Washington, DC: American Psychiatric Association, 2000.

Reynolds, Cecil R., and Erin D. Bigler. Clinical Assessment Scales for the Elderly. San Antonio, TX: The Psychological Corporation, 2001.

Ali Fahmy, Ph.D.

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Clinical Laboratories Improvement Act


Laboratory tests are used to assist medical personnel in diagnosing disease, measuring treatment success, or evaluating the general health status of a person. All laboratories analyzing specimens taken from humans for chemical, biological, or microscopic testing are required to meet national quality standards. The impetus for developing these standards arose from accusations that certain laboratories were using untrained and overworked employees to perform Pap smear testing. Women were dying of cervical cancer not identified until the disease had progressed; a comparison with previous test results showed abnormal cells that had been missed in the earlier tests. As the legislation addressing this public health concern developed in the United States Congress, testimony supported rules and standards for all human testing.

In 1988 Congress passed legislation entitled the Clinical Laboratory Improvement Amendments (CLIA), which required all laboratories doing human testing to meet standards which were verifiable by inspection and proficiency testing (i.e., specimens sent to grade laboratory performance). Prior to this law only laboratories that accepted specimens across state lines and those performing tests for Medicare/Medicaid-insured persons were regulated by the federal government. A small number of states had either personnel or laboratory licensing procedures addressing quality performance.

The Secretary of the U.S. Department of Health and Human Services was instructed to prepare rules outlining the requirements for certified laboratories. These rules set minimum standards for educational, training, and experience qualifications for directors and supervisors; specified required documentation of quality assurance and quality control programs; and defined adequate performance in proficiency testing. Between 1990 and 1998 additional rules were drafted and revised to state the specific laboratory quality and documentation requirements, categorization of test difficulty, rules for allowing states and private groups to accredit laboratories, and penalties for failing to meet the standards. The standards were geared toward addressing complexity of testing rather than location or size of laboratory. Previous regulations had emphasized education and training of laboratory analysts and technical managers rather than laboratory processes and quality monitoring of testing. A major difference between these rules and previous laboratory regulations was the segmentation of laboratories into levels of technical proficiency.

Congress recognized there were certain tests which could be performed with little danger of harm to the patient even if performed incorrectly, were simple and easy to use, or approved by the U.S. Food and Drug Administration for home use. These were waived from the regulatory requirements. Most of these tests are performed in nonprofessional laboratories (e.g., nursing homes, small or rural clinics, and physician's offices). These testing sites were excused from meeting the standards only if they applied to do so and agreed to use the tests only as designed and marketed by the manufacturer.

Early expectations were that over 200,000 laboratories would apply for certification, but closings and consolidation limited that number to 150,000 by the mid-1990s. In 1999 there were nearly 170,000 laboratories certified to perform tests on humans. Over half of those were small laboratories doing limited procedures in clinics or small testing facilities. Concerns about restricted access to laboratory services as a result of this user-paid program were never realized.

Ronald L. Čada

(see also: Assurance of Laboratory Testing Quality; Diagnostic Testing for Communicable Diseases; Laboratory Technician; Practice Standards for Communicable Diseases; Regulatory Authority )


"Medicare, Medicaid and CLIA Programs: Regulations Implementing the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88); proposed rule.1990." Federal Register 55:20,89620,959.

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Clinical Breast Examination


The clinical breast examination is an examination of the breast performed by a health care professional. The exam involves inspecting the breasts to look for asymmetry, skin dimpling, or masses. The breasts are subsequently palpated in both the upright and recumbent positions. The axillary and supraclavicular regions are palpated for the presence of abnormal lymph nodes. The American Cancer Society recommends a clinical breast examination by a health professional every three years for women between the ages of 20 and 39, and yearly for women aged 40 and older. Studies demonstrate increased breast cancer detection with a combination of clinical breast exam and mammography compared to mammogram alone. Despite this, no study has demonstrated a reduction in mortality resulting from the addition of the clinical breast exam to mammographic screening.

Clifford Hudis

Arti Hurria

(see also: Breast Cancer; Breast Cancer Screening; Breast Self-Examination; Mammography )


Morrow, M. (2000). "Physical Examination of the Breast." In Diseases of the Breast, eds. J. R. Harris, M. E. Lippman, M. Morrow, and C. K. Osborne. Philadelphia, PA: Lippincott Williams & Wilkins.

Taves, D. H.; McCurdy, L. I.; and Sparrow, R. K. (1996). "The Relative Diagnostic Impact of Screening Mammography and Physical Examination." Canadian Association of Radiologists Journal 47:257259.

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clinical medicine

clinical medicine n. the branch of medicine dealing with the study of actual patients and the diagnosis and treatment of disease at the bedside, as opposed to the study of disease by pathology or other laboratory work.

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