Appointments are made only by a referral from a physician.  Physicians should call Children's Direct at 800.678.HELP (4357) to make a referral.
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The Undiagnosed Mendelian Disorders Clinic specializes in the evaluation of children and adults with severe and complex medical conditions for which a diagnosis has not been made by traditional testing methods (physical exam, imaging studies, metabolic evaluation, single gene testing or chromosomal microarray analysis).  Evaluation will include:

  • Review of the individual’s existing medical records
  • In-depth physical examination
  • Discussion of family history 

Following the evaluation, testing recommendations will be discussed with the family.  In most cases, testing will include clinical whole exome sequencing.

Exome Sequencing

Exome sequencing is a test in which the coding regions for the majority of a person’s genes are examined all at the same time.  It is the most powerful genetic test currently available to aid in patient diagnosis.  During the clinic visit, the family is counseled about the benefits and risks of the test (pre-test genetic counseling).  Because the study looks at all of the patient’s genes, it may reveal information unrelated to the patient’s current health concerns, such as information about whether the parents are related to each other and about health risks that may not occur until adulthood.  A consent form is used to allow families to opt in or out of these different types of information.  The test requires DNA from the patient (usually from blood).  Samples from the patient’s biological parents are also included for interpretation, as are samples from other affected family members, if available.

If the clinical exome sequencing reveals a diagnosis for the child, as occurs in 25-40% of cases, genetic counseling will be provided to the family.  Recommendations for medical management will be made in collaboration with the referring physician and evaluations by additional specialists may be recommended based on the test result. 

If the clinical exome sequencing does not reveal a diagnosis, the family may elect to participate in research studies that aim to find new genes associated with the patient’s medical concerns.

How Refer a Patient

All patients wishing to be seen in the Undiagnosed Mendelian Disorders Clinic should be referred by the specialist provider most familiar with their condition.  To do so, the provider should call Children's Direct at 800.678.HELP (4357) and ask to speak with the Undiagnosed Mendelian Disorders Clinic counselor in the Division of Genetics and Genomic Medicine.  The referring physician must provide written documentation of the patient’s symptoms and previous testing.  This information is reviewed by the genetics team prior to placement in the Undiagnosed Mendelian Disorders Clinic.  If a patient has had limited diagnostic testing at the time of referral, the patient may first be seen through the general genetics clinic for initial assessment.

Why Choose Us?

St. Louis Children’s Hospital is consistently ranked among the nation’s best pediatric hospitals by U.S. News & World Report, the most comprehensive source of quality-related information on U.S. pediatric hospitals. We follow one simple mission – to do what’s right for kids. That mission comes to life through medical discovery, innovative therapies and compassionate care.

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We offer world-class care to children thanks in part to generous gifts from hundreds of people who have joined us in making health care better for all children. This philanthropic support enables us to fulfill our mission to do what's right for kids.

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