Pediatric Genetics

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What is a pediatric geneticist?

A pediatric geneticist is a doctor with special training in pediatrics and genetics. They are able to recognize rare genetic syndromes and conditions in children and help families of children with these conditions to receive appropriate medical care. Pediatric geneticists often work with genetic counselors. Genetic counselors are people who are trained to give families information about genetics and genetic conditions.

Who should see a pediatric geneticist?

There are many different things that bring children and their families to a pediatric geneticist.

  • Children who are known to be at risk for a genetic condition or syndrome because someone in their family has a genetic condition
  • Children with more than one birth defect
  • Children with developmental delay or mental retardation that do not have a known cause
  • Children with multiple unexplained health problems whose parent or physician requests evaluation

Why should I see a pediatric geneticist?

When children have health conditions, their parents often have questions like-

  • Why does my child have this health condition?
  • Could my future children or my child’s children have a similar health condition?
  • Where can we get more information?

Sometimes it is difficult to get clear answers to all of these questions, however, a genetic specialist can help give information about these rare conditions.

What does a pediatric geneticist do?

An initial outpatient visit usually lasts about 90 minutes. The patient is examined and, with permission, photographs may be taken. At the end of the visit, all findings are reviewed with the patient's family and recommendations are made. During the visit you can expect the geneticist and genetic counselor/genetic nurse to:

  • Work with the family to outline their family history and a three-generation family history, including both sides of the family. This family history, also called a pedigree, may reveal an underlying genetic issue in the family.
  • Diagnose and provide detailed information about genetic conditions.
  • Recommend and interpret genetic testing and give the family more information about the child’s health condition.
  • Recommend appropriate treatment and coordinate care.
  • Refer to resources.

What is a birth defect?

A birth defect is a health problem or physical change, present in a baby at the time he/she is born.  Some birth defects may be minor but other birth defects may be more serious, like a heart problem. Birth defects are also called congenital anomalies or congenital abnormalities. Congenital means "present at birth". Anomalies and abnormalities mean that there is a problem with a baby.

What causes birth defects?

Both genetic and environmental factors, and a combination of the two, can cause birth defects. Some birth defects are inherited in a predictable pattern and caused by single gene changes or chromosome anomalies. Environmental factors or environmental substances that can cause birth defects are called teratogens. They include alcohol, certain drugs/medications, infections, and certain chemicals. More information on teratogen exposure.

However, other birth defects appear to be caused by a combination of one or more genes and environmental exposures. This is called “multi-factorial inheritance.” In some cases, a person may inherit one or more genes that make him/her more likely to have a birth defect if he is exposed to certain environmental substances (such as cigarette smoke). These individuals have a genetic predisposition to a birth defect. But if the individual is not exposed to the environmental substance before birth, he probably won't have the birth defects. Genetic inheritance patterns are described in more detail here.

What if my child has a birth defect?

You may be interested in having your child evaluated by a pediatric geneticist to identify if the birth defect could be part of an underlying genetic syndrome. A genetics evaluation may give you and your family more information about the child’s prognosis and if there is a recurrence risk for future pregnancies.

What is a family history?

In medicine, a family history is part of a person’s medical history. Questions are asked to find out whether a person has tendencies toward a particular disease based on their family’s combination of shared genes, environment, behaviors and culture.

How is a family history helpful?

Knowing your family history can give you a lot of information about your health risks and the risks for your children.

  • It can help you learn about diseases or conditions that you have a risk for getting
  • It can point out behaviors (smoking or inactivity) or environmental exposures (secondhand smoke, farm chemicals) that may increase your risk or your children’s risk for disease
  • It can help you and your doctors know what health problems you should be on the lookout for in yourself and your children so that problems can be found early or prevented

Where can I learn more about how my family history affects my health?

The United States Department of Health and Human Services has information about how you can ask your family about your family history.  Use their family history tool to record a family history and see what you can learn.

Genetic Syndromes

Chromosomal Disorders

Genetic disorders can occur when there is too much or too little chromosomal material or when an abnormal rearrangement (translocation) is present. Chromosomes, which are structural elements containing genes, normally occur in 23 pairs. The first 22 are called autosomes and the last pair is called the sex pair: XX (female) and XY (male).

Resources
Down Syndrome http://ghr.nlm.nih.gov/condition=downsyndrome
Trisomy 18 http://ghr.nlm.nih.gov/condition=trisomy18
http://www.trisomy.org/index.php
Trisomy 13 http://ghr.nlm.nih.gov/condition=trisomy13
http://www.trisomy.org/index.php
Turner syndrome http://ghr.nlm.nih.gov/
http://www.turnersyndrome.org/
Deletion 22q11.2 (DiGeorge, VCFS) http://ghr.nlm.nih.gov/condition=22q112deletionsyndrome
http://www.22q.org/
Cri du chat (5p-) http://ghr.nlm.nih.gov/condition=criduchatsyndrome
Williams Syndrome http://ghr.nlm.nih.gov/condition=williamssyndrome
http://www.williams-syndrome.org/
Smith Magenis http://ghr.nlm.nih.gov/condition=smithmagenissyndrome
http://www.prisms.org/start.htm
Other chromosomal anomalies http://www.chromodisorder.org/CDO/

Single Gene Disorders

Genetic disorders can also result when a change or mutation occurs in a gene. Genes carry the bits of information which determine the growth and function of an individual. Half of our genes are inherited from our mother and half from our father. In some cases only having one mutation in a gene will result in a genetic disorder. Other genetic conditions result from two genetic mutations, one inherited from the mother and the other from the father. Genetic inheritance patterns are described in more detail here.

Resources
Cystic fibrosis http://ghr.nlm.nih.gov/condition=cysticfibrosis
http://www.cff.org/
Rett syndrome http://ghr.nlm.nih.gov/condition=rettsyndrome
http://www.rettsyndrome.org/
Sickle cell http://ghr.nlm.nih.gov/condition=sicklecelldisease
http://www.dshs.state.tx.us/newborn/sickle.shtm
http://www.sicklecellsupportgroup.org/
Duchenne muscular dystrophy (DMD) http://ghr.nlm.nih.gov/condition=duchenneandbeckermusculardystrophy
Fragile X http://ghr.nlm.nih.gov/condition=fragilexsyndrome
Neurofibromatosis http://ghr.nlm.nih.gov/condition=neurofibromatosistype1
Marfan http://ghr.nlm.nih.gov/condition=marfansyndrome
Ehlers Danlos http://ghr.nlm.nih.gov/condition=ehlersdanlossyndrome
Hemophilia http://ghr.nlm.nih.gov/condition=hemophilia
PKU http://www.dshs.state.tx.us/newborn/pku.shtm
http://ghr.nlm.nih.gov/condition=phenylketonuria
Tay Sachs http://ghr.nlm.nih.gov/condition=taysachsdisease
Neurofibromatosis http://ghr.nlm.nih.gov/condition=neurofibromatosistype1

Genetic Testing 

Chromosome Analysis

Each cell in the body contains 46 chromosomes: 22 pairs of identical chromosomes and either two X chromosomes (in a female) or one X and one Y chromosome (in a male). Each chromosome contains many genes which are the blueprints that control our development.

To study chromosomes, cells (usually from a blood sample) are grown in the laboratory. The cells are broken open so that the chromosomes spread out on the microscope slide. The chromosomes are then stained so that they can be viewed under the microscope and analyzed

Fluorescence In Situ Hybridization (FISH) Studies

In FISH, fluorescent molecules attach to specific areas of the chromosome. This allows the laboratory to study smaller areas of the chromosome than what can be seen in normal chromosome studies. It also allows the laboratory to count the number of certain chromosomes without having to wait for the cells to grow.
FISH may be requested if your physician is suspicious of a genetic disorder where a very small piece of chromosome material is missing—a piece so small that it wouldn’t be seen under the microscope in normal chromosome studies.

Array Comparative Genomic Hybridization (CGH) Testing

Microarray-based  (array CGH) is a method for detecting extremely small chromosomal imbalances in patients. Array CGH enables the laboratory to look at all of a person’s genetic material or DNA at a level that is not possible with routine chromosome testing.  This is also called  genome-wide screening.

Single Gene Testing  

Involves looking at the DNA, the chemical database that has instructions for your body's functions, of specific genes. Genetic testing can reveal changes in your genes that may cause illness or disease.

Although genetic testing can provide important information for diagnosing, treating and preventing illness, there are limitations. For example, if you're a healthy person, an abnormal result from genetic testing doesn't always mean you will develop a disease. On the other hand, in some situations, a normal result doesn't guarantee that you won't have a certain disorder.  Additionally, some genetic syndromes do not have testing available and instead the diagnosis is made by your geneticist on a clinical basis.

Resources

Early Childhood Intervention (ECI)   

A Texas program for families with children, birth through three, with disabilities and developmental delay.  ECI supports families to help their children reach their potential through developmental services.  Services are provided by a variety of local agencies and organization across Texas.

National Organization for Rare Disorders (NORD)

This site is dedicated to helping people with rare diseases and assisting the organizations that serve them.  NORD is committed to the identification, treatment and cure of rare disorders through programs of education, advocacy, research and service.

Genetic Alliance

The Genetic Alliance is an international organization of families, professionals and genetic support organizations that works to improve the quality of life for individuals dealing with a genetic condition.  This site offers disease specific information and resources as well as a “helpline” with direct contact with a genetic counselor for more information or to discuss questions and concerns. 

March of Dimes 

Provides information on birth defects, genetic disorders and multiple pregnancy issues.  Fact sheets on specific genetic conditions are available.

Genetics Home Reference - National Institute of Health

A comprehensive review of all most genetic conditions categorized by organ system, genes and chromosomes.  Consumer friendly information on the effects of genetic variation.

Chromosome Deletion Outreach

A nonprofit organization for parents with children affected by a wide range of chromosome disorder, including deletions, duplications, trisomies, inversions, translocations and rings.

Last Updated August 24, 2009

Last updated March 05, 2013