Lurie Children’s Trisomy 9 Mosaic syndrome (T9M) and Chromosome 9 Program is the first clinic in the world dedicated to the care and research of individuals with T9M and other variants on Chromosome 9, which are rare genetic conditions.
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What Are Chromosome 9 Variants?
What Are Chromosome 9 Variants?Our genetic instructions are made of DNA, which is packaged into structures called chromosomes. Most individuals have 46 chromosomes, arranged in 23 pairs, including one copy of chromosome 9 from each parent. Each chromosome 9 has two arms: a short arm, called the p arm (shown at the top in the diagram on the right), and a long arm, called the q arm (at the bottom).
When there is deleted (missing) or duplicated (extra) genetic material, this leads to changes called copy number variants. Copy number variants are named based on their location using a standardized system of letters and numbers. The size of the deletion or duplication can vary and may consist of portions of an arm, the entire short (p) or long (q) arm, or the entire 9th chromosome. For example, having an extra short arm of chromosome 9 would be called 9p duplication.
Having an entire extra chromosome is called a trisomy. Individuals with T9M have some cells (basic building blocks of our body) that have an extra copy of the 9th chromosome, leading to three chromosomes 9 in those cells instead of the usual two. The term "mosaic" means this extra chromosome is only present in some cells, not all. Having an extra copy of chromosome 9 or having a partial deletion or duplication of chromosome 9, even in a portion of the body, can lead to a range of health problems including developmental delay, growth issues, and different types of birth defects.
The T9M and Chromosome 9 Clinic aims to evaluate and support individuals with T9M and chromosome 9 copy number variants and provide opportunities to participate in available research if families are interested.
Why Choose Lurie Children's?
The genetic specialists in this clinic, Mindy Li, MD, and genetic counselor Kelsey Hogan, MS, CGC, both have experience with neurodevelopmental disorders, T9M, and other chromosome 9 variations. Dr. Li is the primary author of a publication on individuals with T9M that includes suggested clinical screening guidelines for this disorder. Our team is dedicated to supporting and advocating for both the physical and emotional needs of children and their families.
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Conditions We Treat
- Trisomy 9 mosaic syndrome (T9M)
- Chromosome 9 Variants (such as 9p Duplications, 9p Deletions, 9q Deletions)
Our Specialists
Mindy H. Li, MD
Attending Physician, Genetics, Genomics and Metabolism
Kelsey Hogan, MS, CGC
Genetic Counselor II, Genetics, Genomics and Metabolism
What to Expect
First T9M and Chromosome 9 Clinic Visit
During your visit, you’ll meet our team, including geneticist Dr. Mindy Li and genetic counselor Kelsey Hogan, MS, CGC. Additional team members, such as medical trainees, may also be present.
We will review your child’s medical, surgical, and family history, including prenatal, birth, and developmental milestones. A physical exam will be conducted, and we’ll explain your child’s genetic test results. If you have copies of these results, please bring them to the appointment.
Our team will discuss recommended next steps, such as medical imaging, baseline screenings, or referrals to specialists as needed.
Follow-up Visits
After the first visit, we may recommend regular follow-up with our team. This will vary depending on each family's needs but may be as frequently as annual visits. However, if any concerns arise between visits, our team is always available to help the children and families in our care.
Make an Appointment
To schedule a first-time or return appointment, please call the Division of Genetics directly. This clinic occurs in person, but patients who live in Illinois may also request a telemedicine visit. Due to state laws, patients who live outside of Illinois may be seen by telemedicine on a limited basis only after an initial in person visit.
Our Location
Ann & Robert H. Lurie Children's Hospital of Chicago
225 E. Chicago Ave.Chicago, Illinois 60611
312.227.4000
Resources & Support
For additional information on T9M, please visit the following sites:
- Trisomy 9 mosaic syndrome: Sixteen additional patients with new and/or less commonly reported features, literature review, and suggested clinical guidelines
- Unique – Understanding Rare Chromosome and Gene Disorders: Mosaic Trisomy 9 Information Booklet
- National Organization for Rare Disorders (NORD): Mosaic Trisomy 9
- SOFT (Support Organization for Families with Trisomy)
There is also an active private Facebook group if families are interested in connecting with others who also have a child with T9M.
For additional information on other Chromosome 9 Variants, please see:
- Unique – Disorder Guides (there are multiple guides for disorders listed in the Chromosome 9 section)
Research
Our team has planned research projects related to T9M and chromosome 9 copy number variants, including natural history studies to learn about the growth, development, and other medical findings of individuals with T9M and chromosome 9 variants of all ages. Although there is currently no treatment for these disorders, we hope by learning as much as we can about T9M and chromosome 9 variations, we can improve the overall health care for these individuals.