Dysmorphology

Dysmorphology is the study of congenital anomalies—or birth defects—in the human body. Such anomalies typically result from environmental exposures, genetic causes, or some combination of environmental and genetic influences. Dysmorphologists study both genetic and congenital birth defects, which can be minor or severe and may affect appearance, bodily function, and/or mental and physical development. The field of dysmorphology, which dates back to the 1960s, is primarily focused on describing and categorizing various birth defects, diagnosing dysmorphic syndromes, and treating patients who have birth defects and birth defect-related conditions. When a physician of any kind consults with patients and their families on matters related to morphological birth defects, he or she inherently takes on the role of a dysmorphologist. Physicians acting as dysmorphologists are able to identify the risks for birth defects and provide clinical supports for patients and their families. As such, a clear understanding of dysmorphology is necessary for many healthcare providers.

Background

Birth defects are problems that develop while a baby is developing in the womb. While some birth defects are relatively minor, others can have severe consequences. Minor birth defects are often harmless, but more severe anomalies may require long-term medical treatment or could even prove fatal. Different types of birth defects can affect appearance, bodily function, or mental or physical development. The majority of birth defects initially appear in the first trimester of a pregnancy.

The potential causes of birth defects include genetic and non-genetic factors. Genetic abnormalities are a result of flaws that occur when a gene undergoes a mutation. Mutations can mean that all or part of gene may be missing. Such defects are present from conception and cannot be prevented. Specific genetic defects can be passed on to a child from one or both parents and can be present in multiple generations of a family. While the genetic causes of birth defects are often easy to identify, non-genetic causes are more difficult to pinpoint. Smoking, drinking alcohol, or using illegal drugs during pregnancy may cause some birth defects. Others may be caused by exposure to toxic chemicals, infections, or even certain medications during pregnancy. Although all pregnant women face some risk of having a child with a birth defect, those who have a genetic history of birth defects, consume potentially dangerous substances while pregnant, receive inadequate prenatal care, have untreated viral or bacterial infections, or take high-risk medications may be at greater risk than others. Women who become pregnant when they are 35 or older may also be more likely to have a child with a birth defect.

There are two main types of birth defects: structural and functional or developmental. Structural birth defects result in missing or malformed body parts. Heart defects, cleft lips and palates, clubfoot, and spina bifida are all examples of structural birth defects. Functional or developmental birth defects cause specific body parts or entire body systems to not work as they should. Such defects often lead to intellectual or development disabilities. Children and adults with functional or developmental birth defects may also experience sensory problems, metabolic defects, or nervous system problems. Down syndrome, sickle cell disease, and cystic fibrosis are all examples of functional or developmental birth defects.

Overview

Dysmorphology is a field of medicine concerned with the study of congenital structural anomalies and their causes. It is part of a broader medical specialty known as clinical genetics, which provides diagnostic services and genetic counseling for individuals or families who have or are at risk for genetic conditions like chromosomal abnormalities, muscular dystrophy, familial cancer, and birth defects. Dysmorphology first emerged when pediatrician and clinical geneticist David W. Smith coined the term in the 1960s. Smith’s work was instrumental in the development of dysmorphology and the effort to identify and categorize the various causes of cognitive disability.

Physical birth defects arise from errors that occur as an embryo develops inside the womb during a pregnancy. As a result, the study of dysmorphology sheds light on physicians’ understanding of how various genetic and non-genetic factors influence human morphogenesis, the process by which tissues and organs are formed and differentiated. As the field of dysmorphology grew, the recognition of various syndromes and their effect on patients eventually allowed researchers to identify the specific genes that cause those syndromes. This allowed doctors to gain a better understanding of how those genes cause disorders and what role they play in normal embryonic development. These advancements have led dysmorphology to become an important field that contributes significantly to the scientific understanding of birth defects and how they occur.

Proper dysmorphologists are board-certified pediatricians who, in addition to their normal medical education, undergo two to three additional years of specialized training in the causes, treatment, and prevention of birth defects. That being said, any physician who treats or otherwise counsels patients with birth defects and their families is said to be effectively functioning as a dysmorphologist. Dysmorphologists have many responsibilities when it comes to helping patients and families understand and cope with birth defects. Much of their work is focused on properly diagnosing the patient’s condition. In order to arrive at an accurate diagnosis, dysmorphologists must gather any pertinent information tied to family history and pregnancy history and evaluate any structural or developmental problems discovered either before or after birth. Having done that, they then take the time to interpret all available data and use that information to make a specific diagnosis. Dysmorphologists may also order tests as way of confirming or ruling out possible diagnoses. Once a diagnosis has been made, they often seek to provide patients and families with information about how the problem occurred, possible treatment options, and what to expect moving forward. In addition, dysmorphologists help parents who have had a child with a birth defect plan for future pregnancies. They may discuss the likelihood that similar problems may occur with other children, go over ways to prevent recurrences, and review prenatal procedures that could detect a recurrence in the early stages of pregnancy. Dysmorphologists also provide necessary postnatal follow-up care for children with birth defects or other conditions that require support.

Bibliography

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