Genetic Services

young sisters outsideMany diseases that affect children have very clear symptoms, testing and diagnosis. However, there are thousands of conditions that aren’t so easily identified. They require evaluation and testing at the genetic level in order to understand and manage them.

Our board-certified physicians in clinical genetics, clinical cytogenics and clinical molecular genetics help diagnose and manage the most common genetic conditions and birth defects, as well as have unique experience with very rare diseases. Using the latest genetic testing methods and with access to databases of genomic information from around the world, we work tirelessly to find answers for your family so that your child can receive the most appropriate care.

We not only diagnose genetic conditions but also provide recommendations for patients and team up with other CHOC specialists to ensure all of your child’s medical needs are being met.

Our genetic services include:

  • Diagnosis of a genetic condition by doing a complete review of the patient’s personal and family history, a complete physical examination and/or genetic testing
  • Education and understanding about how or why a condition occurred (in most cases)
  • The chances for the condition to reoccur in your family
  • The chances for other family members to have the condition or pass it on
  • Recommendations for managing the disorder
  • Resources, support and connections to other families who have a child with the same condition.

What to Expect

We know that people have different feelings when it comes to genetic evaluation and testing. Some may feel anxious or relieved to have a diagnosis, while others may feel better not knowing or having as much information. There is no right or wrong way to feel, and our team compassionately works with every family at their level of comfort.

While the field of genetics is rapidly advancing, genetic testing is not 100 percent accurate. It can also reveal findings that cannot be completely explained or interpreted. That means genetic testing may not always provide answers to all of your questions or provide a diagnosis. Please also note that a negative test result does not mean that your child does not have a genetic condition. It is also important to know that many genetic conditions can be diagnosed clinically without a genetic test, which is why we may do a complete physical exam and review past medical history and family history of your child, but not always recommend genetic testing.

We recommend a genetics evaluation and genetic counseling prior to any testing in a patient or family member. During your appointment, we will talk one-on-one with your family to explain a suspected condition, whether we think genetic testing is needed or available, and if so, the possible results that can be expected.

The CHOC Difference

What We Treat

There are more than 3,000 known genetic diseases—and counting. The following is a limited list of some of the more common conditions we treat, though we treat many others as well.

Genetic Syndrome Causes Cleft Lip, Palate in Sisters

The Snyder family

Just like most sisters, Tristyn and Raigyn Snyder will share toys, clothes and friends throughout their lives. They also share something unique: a genetic condition called Van der Woude syndrome. Van der Woude syndrome is the most common single-cause of cleft lip and palate. Individuals with VWS may have a cleft lip with or without a cleft palate, a submucous cleft palate, lip pits along the lower lip, or any combination of these features.

Innovative Programs, Specialized Expertise

Our genetics team oversees and participates in a number of multidisciplinary programs with other pediatric specialists at CHOC.

The CHOC Neurofibromatosis Program is one of a select group of designated affiliate clinics with the Children’s Tumor Foundation. With experts in genetics, neurology, neurosurgery, oncology and orthopaedics, we provide comprehensive care and diagnostic testing to more than 150 children a year who have neurofibromatosis type 1. Learn more about our Neurofibromatosis Program.
From cleft lip and cleft palate repair to complete facial reconstruction, CHOC uses the very latest and advanced techniques to help a child with a craniofacial disorder look, eat and speak just like other children. The American Cleft Palate-Craniofacial Association has endorsed CHOC as an official Cleft and Craniofacial Team, meaning our program has met specific guidelines for working as an interdisciplinary team. Learn more about our Cleft and Craniofacial Program.
Our genetic specialists work closely with CHOC endocrinology specialists and pulmonologists to treat Prader-Willi syndrome, a rare genetic disorder that causes decreased muscle tone, mild-to-moderate intellectual disability and an intense appetite.
Through a designation by the Tuberous Sclerosis Alliance, our specialized clinic treats children with tuberous sclerosis, a rare disorder that can cause epilepsy as well as growths inside the brain, heart, kidney and retinal area of the eye. Because tuberous sclerosis affects different areas of the body, we draw on the expertise of specialists from multiple CHOC disciplines including neurology, genetics, cardiology, nephrology, neuropsychology, neurosurgery and ophthalmology. Learn more about our Tuberous Sclerosis Program.
CHOC has the only pediatric program in Orange County designated by the Muscular Dystrophy Association to help families understand and manage muscle disease. That means in addition to an entire team of CHOC specialists who care for your child, we also partner with the MDA to offer access to national research and community support. Learn more about our Muscular Dystrophy Association Clinic.
The CHOC Down Syndrome Program bridges community services and clinical specialists to ensure that every patient’s needs are being met. The clinic is designed to complement primary care services by providing supplementary medical care with an emphasis on preventive medicine and case management services. Learn more about our Down Syndrome Program.
CHOC has the only pediatric cystic fibrosis affiliate care center of the Cystic Fibrosis Foundation in Orange County. Our geneticists partner with CHOC pulmonologists and other specialists to treat medical problems associated with cystic fibrosis. Our convenient, multidisciplinary program allows patients to see all of their cystic fibrosis care team specialists at the same appointment. Learn more about our Cystic Fibrosis Center.

Testing for Genetic Conditions During Pregnancy

Many genetic abnormalities can be diagnosed before birth. Your doctor may recommend genetic testing during the pregnancy if you or your partner have a family history of genetic disorders or you have had a fetus or baby with a genetic abnormality. Testing options include blood tests, amniocentesis and chorionic villus sampling (CVS).

prenatal testing ultrasound

Frequently Asked Questions about Genetics

Genetics is the study of the patterns of inheritance—how traits and characteristics are passed from parents to their children. Humans have an estimated 25,000 different genes that each controls a specific function of the body. These genes have collections of DNA that make up our chromosomes (linear structures in the nucleus of cells). Nearly every cell in our body contains 46 chromosomes arranged in 23 pairs.

Genes are lined up on the chromosomes in specific positions and locations. Although these locations are the same for each pair of chromosomes, the DNA content of those genes may be similar or different. Just as traits, such as blue eyes and curly hair, are passed from the genetic information of the parents to a baby, inherited diseases and abnormalities can also be passed on. Some disorders are autosomal recessive, meaning that one copy of an abnormal gene must be received from both parents, for the child to be affected. Other disorders are autosomal dominant, meaning one copy of an abnormal gene may come from only one parent for the disorder to occur. Other genetic conditions can happen spontaneously, meaning the genetic change happened in a child randomly at the time of conception and was not inherited from either parent.

When a gene is abnormal, or when entire chromosomes are missing or duplicated (also known as aneuploidy), defects in the structure or function of the body’s organs or systems can occur. Mutations in a specific gene can result in a specific disorder, such as cystic fibrosis, which is a recessive genetic disease. Meanwhile, abnormalities in a specific chromosome can result in conditions such as Down syndrome, a condition that occurs when a baby receives three copies of the #21 chromosome.
There are approximately 25,000 genes contained on the 46 chromosomes in each cell of the human body. This means that one chromosome contains thousands of genes. A person can have normal chromosomes in number and structure, but have a mutation in one or more of the genes on the chromosomes. This is called a single gene defect. Similarly, a person can have normal genes but have a chromosome abnormality, which is when pieces of a chromosome are missing or duplicated. This is an important distinction to make. Testing for single gene disorders and chromosome abnormalities uses different technologies. Your genetics doctor can provide more information.
The following is a general checklist of characteristics that may indicate a child has a genetic defect. This is not an all-inclusive list. When two or more of these items are found, there may be a need for a genetic evaluation of the child.

Birth Defects
  • Cataracts
  • Cleft lip and/or cleft palate
  • Congenital heart defects
  • Contractures (stiff joints)
  • Diaphragmatic hernia
  • Genital malformations
  • Genitourinary malformations
  • Structural eye abnormalities (coloboma, glaucoma, cataracts)
  • Craniosynostosis (misshapen skull)
  • Missing or extra fingers or toes
  • Missing or incomplete arms or legs
  • Spina bifida or open spine defects
Chronic Diseases
  • Bleeding disorders
  • Childhood cancers
  • Kidney or urinary tract disease
  • Slow growth or short stature
  • Cystic fibrosis
  • Sickle cell disease
  • Thalassemias
Developmental Problems
  • Autism
  • Developmental delay or disability
  • Failure to thrive
  • Large size (macrosomia)
  • Learning disability
  • Loss of developmental skills
  • Low muscle tone (hypotonia)
  • Mental illness
  • Intellectual disability
  • Speech problems
  • Seizures
Sensory Deficits
  • Extreme farsightedness
  • Extreme nearsightedness
  • Bilateral hearing loss
  • Retinal or other visual problems
Physical Features
  • Ear abnormalities
  • Unusually shaped eyes
  • Facial features that are unusual or are very different from other family members
  • Brittle or sparse hair
  • Excessive body hair
  • White patch(es) of hair
  • Large or small tongue
  • Misshapen teeth
  • Missing or extra teeth
  • Loose or stiff joints
  • Unusually tall or short stature
  • Webbing between fingers or toes
  • Excessive skin over the body
  • Unusual birthmarks
  • Increased or decreased sweating
Family History of a Genetic Disorder
We recommend a genetics evaluation if a first-degree or second-degree relative of a child has a genetic condition. A genetics evaluation is recommended prior to any testing of the child.

Each child should be evaluated on an individual basis since some of these features, when isolated, are found in the general population and are not associated with a genetic disease. Symptoms of genetic diseases may resemble other conditions or medical problems. Always talk to your doctor for a diagnosis and a complete list of characteristics.
A genetics evaluation involves meeting with a geneticist and genetic counselor(s) to review the following:
  • Your child’s medical history
  • Your child’s birth history
  • Your family tree going back three generations
  • A head-to-toe physical examination.
The purpose of a genetics evaluation is to identify an underlying genetic condition in order to provide information to your family, as well as to provide genetic counseling about the risk of recurrence. Once a genetic evaluation is complete, we may or may not recommend genetic testing, depending on the condition that we suspect your child has.
After your child’s genetic evaluation, our genetic specialist may recommend a genetic test, and will explain the test in easy-to-understand terms. The following genetic tests are commonly used for children.

Diagnostic Testing
Most of the genetic tests performed on children at CHOC are done for diagnostic reasons. Diagnostic testing is used to identify or confirm the diagnosis of a disease or condition in a person or a family. Diagnostic genetic testing often gives a “yes” or “no” answer, but not always. This testing can be helpful in determining the course of a disease and the choice of treatment or support. Examples of diagnostic testing include chromosome analysis–which looks for chromosomes that are extra or missing–and gene testing (sequencing), which determines if the molecular sentence of a gene is correct (i.e. if the letters of DNA in the gene are in the appropriate order). To test chromosomes, we use a sample of blood. For testing genes, we may take samples of a child’s blood or saliva, or swab the inside a child’s cheek (buccal swab).

Newborn Screenings
Screenings are performed on newborns soon after birth at every hospital in California. This screening tests for about 80 different genetic conditions. If a baby tests positive for any of these conditions, the test results are sent to labs throughout the state for further evaluation, including the CHOC Children’s Metabolics Lab. From there, the metabolics team at CHOC, along with the genetics team, is available to help you manage any condition that your baby may have. Learn more about metabolic tests at birth.

Prenatal Screening and Prenatal Diagnosis
Prenatal screening and diagnosis methods are used to diagnose a genetic disease or condition in the developing fetus. This includes maternal serum screening, prenatal ultrasound (sonograms), amniocentesis, chorionic villus sampling (CVS), and percutaneous umbilical blood sampling (PUBS). Learn more about prenatal genetic screening and prenatal diagnostic testing.
In most cases, no, genetic conditions cannot be prevented or avoided. Most genetic conditions occur at the time of conception. Some are inherited from a parent(s) and others happen spontaneously for the first time in a child. These defects are not caused by an action or inaction on the parents’ part either before or during the pregnancy.
Yes. Every human has millions of variances in their DNA when compared to other humans. Many genetic conditions may have different features even among affected people within the same family. We are all unique and not everyone will have the same lifetime experience. Some genetic conditions may not manifest in every person who has a genetic change or mutation. However, knowing about an underlying genetic condition is important so that parents know if there is a risk for the condition to be passed on to future generations.

Genetics Locations

To make a genetics appointment at CHOC, please call 888-770-2462.

Genetic services are provided on the third floor of the Bill Holmes Tower.

1201 W. La Veta Ave.
Orange, CA 92868

Our genetic specialists also see patients at our affiliate laboratory, The Genetics Center.