Frequently Asked Questions

A CNV (copy number variant) is a type of genetic change where a small section of a chromosome is either missing or duplicated. A microdeletion means that a small piece of a chromosome is missing. When you are born, you have 46 chromosomes in total organized into pairs. You receive 23 from your mother and 23 from your father. Because chromosomes carry your genes, if a tiny section is missing, one or more genes in that area may also be missing. When this happens, your body has only one working copy of those genes instead of two. Some genes work fine with one copy, but others may lead to health or developmental differences. A microduplication is similar in concept, except there is an extra piece of a chromosome. Instead of having two copies of certain genes, a person has three copies in that small region. Some genes function normally and are not affected by this. Others are sensitive to the extra copies, and this may lead to health, learning, and/or developmental differences.

Some rare genetic conditions are caused by a specific, identifiable chromosomal change. If a parent carries a condition like 17q12 deletion, each child may have a 50% chance of inheriting it. However, many cases arise for the first time in a child (called “de novo” changes), meaning the parents do not carry the variant. Even when a genetic change is inherited, the way it affects a person can vary widely. Genetic counseling can help clarify individual likelihood.

This depends on a couple of different factors. Testing parents is usually the first step to determine if the CNV was inherited or de novo (arose for the first time in the child). Testing for other children might be offered if the CNV is found to be inherited. Genetic testing is a personal decision, and a genetic counsellor can help families decide what is right for each individual.

There is a wide variety of symptoms that an individual diagnosed with a CNV may or may not have. For instance, research has shown that 17q12 deletions and duplications have been linked to changes in the functioning of the kidneys, diabetes (MODY5), electrolyte imbalances, developmental and neurodevelopmental differences, and mental health conditions. Baseline screening and monitoring can help families establish a plan that works for them. Symptoms, however, can vary from one person to another, even within the same family. More information about health conditions associated with 17q12 CNVs can be found below: PRISMA 17q12 Infographic 17q12 Deletion 17q12 Duplication UNIQUE Resources

A CNV is not progressive, as the genetic change itself does not worsen over time. However, some related conditions may appear or change with age. For example, kidney function or diabetes may develop or change later in life, electrolyte levels can fluctuate, and neurodevelopmental and mental health conditions can change as life circumstances change.

Symptoms can look very different from one person to another, even within the same family. Your child has the 17q12 CNV plus a different combination of other genes than their parent. Those other genes can increase, decrease, or change how a condition presents itself. Development and environment also play a huge role—early support, stress levels, schooling, therapies, peers, and life experiences can all play a role in shaping how a CNV presents.

After a diagnosis, a genetic counsellor can help your family by referring you for the baseline assessments that you may need. As a parent or caregiver, you can observe your child’s speech, learning, social skills, attention, behaviour, and overall health. If you notice delays or have concerns, seeking support from specialists such as speech, occupational, and physical therapists can be very beneficial. If your child is school-aged, you can work with the school to request evaluations and accommodations like an IEP or a 504 plan. Regular medical checkups can help you adjust supports if needed.

Yes. The 17q12 Foundation has a support group for those diagnosed with either a duplication or deletion. There are also multiple smaller support groups on social media such as Facebook. A genetic counsellor can also help identify support groups and resources that may be a good fit for your family.

Yes. Participating in research studies and patient registries is an important way to advance knowledge and support future discoveries. Find out more about research opportunities from our group and from our partners: PRISMA Research 17q12 Patient Registry