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Frequently Asked Questions

 Frequently asked questions provided by 11q families with answers provided by our chief medical advisor, Dr Paul Grossfeld. For detailed information, please visit our medical articles and concerns and recommendations

What is a deletion? 

Any loss of genetic information.


What is recombination? 

Any rearrangement of genetic material that is frequently associated with also a loss or gain of genetic material.


What are duplications? 

An extra copy of genetic information.


What is Trisomy 11q? 

There is an extra copy of the long arm on chromosome 11.


Are Jacobsen Syndrome pregnancies high risk? 

Pregnancies are not high risk in terms of the mother’s health during pregnancy. For the baby, a C—section is recommended due to the risk of brain bleeds from head trauma from vaginal birth. There is also a higher risk of prematurity. It should be assumed that all infants with JS have the bleeding problem (Paris-Trousseau), which includes a low platelet count and impaired platelet function.  All pregnancies involving a child diagnosed prenatally with Jacobsen syndrome should be managed by a perinatologist, i.e., an obstetrician that specializes in high risk pregnancies.


I have a genetic disease. Can I prevent my child from inheriting it? 

Recurrence can be prevented through preimplantation diagnosis, but the specific mutation needs to be identified. This technology involves in vitro fertilization in which individual fertilized eggs are analyzed for the presence or absence of the specific mutation (i.e., 11q deletion for Jacobsen syndrome). A fertilized egg that does not carry the mutation can then be implanted into the mother, thereby preventing vertical transmission of the mutation from parent to child.


I have Jacobsen Syndrome, what is the probability of passing it on to my children? 

When one parent has Jacobsen syndrome due to an only a deletion in chromosome 11, there is a 50% chance that the deleted chromosome 11 is passed down to a child. Although, a seemingly “normal parent” could be at high risk of having a child with Jacobsen Syndrome if they carry a balanced/chromosomal translocation. When both parents have normal chromosomes, there is about a 1% chance of having a recurrence, likely due to a phenomenon called germline mosaicism.


What are the major protocols doctors need for procedures? 

Major protocols include: bleeding and immunology. Recommended specialists to visit include: pediatric cardiologist, allergy/immunologist, neurologist, hematologist, nephrologist, ophthalmologist, endocrinologist, and a behavioral pediatrician that has experienced in taking care of special needs children.  An additional service that can be very helpful is music therapy.

(hyperlink website: life saving protocols)


Which medications should be avoided with Jacobsen Syndrome? 

Any drugs that interfere with normal platelet function or that could affect the immune system. Popular medications to avoid include ibuprofen and aspirin. Tylenol does not affect platelet function and therefore can be used for treating fever and/or pain, as long as there is no liver or kidney disease.


What does bone marrow failure mean/look like for Jacobsen Syndrome? 

Bone marrow failure is characterized by a decreased ability to produce red blood cells, white blood cells, and/or megakaryocytes (which give rise to platelets).


How do I interpret an MRI? 

Consult with a pediatric neurologist/radiologist to interpret the findings and what potential clinical implications there might be. In general, MRI findings in people with JS are non-specific and are of only limited value in predicting prognosis.  An MRA (magnetic resonance angiogram) IS recommended to assess for the possibility of a brain aneurysm. 

Brain Hemorrhages in Jacobsen Syndrome: A Retrospective Review of Six Cases and Clinical Recommendations


Are all people with Jacobsen Syndrome affected the same way? 

No, there are various clinical phenotypes, or characteristics shown. Even with an identical deletion at the molecular level, individuals can still have a lot of differences due to other factors.


How is growth and appearance affected with Jacobsen Syndrome? 

Growth and appearance vary widely across individuals. Growth is frequently below average. Appearance can be affected by cranial facial alterations including: wide spaced eyes (hypertelorism), down slanting eyes (palpebral fissures), large head (macrocephaly), triangular head shape (trigonocephaly), “carp-shaped” mouth (down turning of the corners), ears low-set and rotated back, and red hair.

Endocrine abnormalities in ring chromosome 11: a case report and review of the literature


How are speech and behavior affected by Jacobsen Syndrome? 

Speech delay is common, especially expressive language. Frequent behavioral problems include attention-deficit/hyperactivity disorder (ADHD) and autism. Impulsive/aggressive behavior can also occur.


Are there sleeping problems with JS?

Common sleep disturbances include: restless sleep, breathing through the mouth, heavy/loud breathing, dry mouth, teeth grinding, and snoring.

Sleep problems in individuals with 11q terminal deletion disorder (Jacobsen Syndrome)


Will learning ability/skills be affected with Jacobsen Syndrome? 

There is a wide range from normal intellectual ability to significant intellectual disability, along with variable motor skills. In most (but not all) cases, the size of the deletion correlates with the severity of the intellectual disability. Without exception, those with a terminal deletion greater than or equal to 12 megabases have the most severe intellectual disability. The majority (but not all) of people with JS are not able to live independently as adults. 


Do people with JS have any special talents? 

Yes! Individuals are capable of various talents, including singing, dancing, being extremely creative, and great social skills. Most people with Jacobsen syndrome are very loving and very trusting.  

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