11q22.2-q22.3 Microdeletion Syndrome

If a prenatal test or a chromosome test after birth returned a diagnosis of “11q22.2-q22.3 microdeletion syndrome,” an unfamiliar term like this can feel overwhelming.

Here is the short answer. This is an extremely rare chromosomal disorder caused by a tiny, congenital loss of genetic material in the 22.2-to-22.3 region of the long arm of chromosome 11. Alongside developmental delay and distinctive facial features, the extent of the deletion can mean long-term monitoring for future tumor risk becomes an important part of care.

This article walks through the underlying chromosomal change, how it differs from the often-confused “11q terminal deletion (Jacobsen syndrome),” the main symptoms, the inheritance pattern, its relationship to prenatal diagnosis and NIPT, the path to a confirmed diagnosis, and treatment and future tumor screening. We draw on public and academic sources including GARD (the U.S. National Institutes of Health), Orphanet, and peer-reviewed literature. Because reliable information on this rare condition is scarce, let’s work through it one point at a time.

1. What Is 11q22.2-q22.3 Microdeletion Syndrome? (The Underlying Chromosomal Change)

11q22.2-q22.3 microdeletion syndrome is a contiguous gene syndrome caused by a congenital loss of the region spanning 22.2 to 22.3 on the long arm of chromosome 11. It is also written as “11q22.2-q22.3 deletion syndrome” or “del(11)(q22.2q22.3).”

An analysis of five cases reported in a U.S. medical journal found that the size of the deletion ranged from 8.6 Mb (megabases) to roughly 14 Mb across cases, with the distal breakpoint falling in a broadly similar location. This region commonly includes the ATM gene (near 11q22.3), which is involved in DNA repair, and the SDHD gene (near 11q23.1), which is involved in tumor development.

The Roles of the ATM and SDHD Genes

The ATM gene normally causes a separate condition called ataxia-telangiectasia (A-T) only when both copies are affected. When just one copy is lost through a microdeletion, A-T itself does not develop, though a slightly increased susceptibility to certain cancers has been discussed in the literature.

The SDHD gene is associated with hereditary paraganglioma-pheochromocytoma syndrome. In a case series published in a U.S. medical genetics journal in 2015, all five reported cases with developmental delay had a deletion that included the SDHD gene, and the authors noted that tumor screening becomes necessary from adulthood onward.

GARD (the Genetic and Rare Diseases Information Center, U.S. National Institutes of Health) lists mild intellectual disability, developmental delay, short stature, low muscle tone, and distinctive facial features as characteristic of this condition. According to Orphanet (ORPHA:444002), the European rare disease database, the global prevalence is estimated at fewer than 1 in 1,000,000 people, underscoring just how rare this condition is.

2. How It Differs from the Often-Confused “11q Terminal Deletion (Jacobsen Syndrome)”

Even when the affected chromosome is the same, the long arm of chromosome 11, a difference in the location and size of the missing region results in a different name and a different set of symptoms. In particular, be sure to distinguish this condition from Jacobsen syndrome, in which the entire telomeric end of chromosome 11 is lost.

Comparison	11q22.2-q22.3 Microdeletion Syndrome (this article)	Jacobsen Syndrome (11q Terminal Deletion)
Location of loss	An “interstitial deletion” — a partial loss within the long arm (22.2 to 22.3)	A “terminal deletion” — the entire long-arm end (from around 23 to the telomere) is lost
Main genes involved	ATM, SDHD, and others	FLI1, ETS1, and many other genes across a wider region
Number of reported cases	An ultra-rare condition with only a handful of cases reported worldwide	A relatively well-known chromosome 11 deletion syndrome with many reported cases
Representative symptoms	Mild-to-moderate intellectual disability, developmental delay, distinctive facial features	Thrombocytopenia (Paris-Trousseau type), heart defects, more severe developmental delay
Future tumor risk	Monitoring for paraganglioma and related tumors when SDHD is deleted	Management centers on blood disorders and heart defects

Because both conditions are described using the “11q” notation, it is easy to assume from the test result alone that they are the same disease. A chromosomal microarray analysis (CMA), which pinpoints the exact location and extent of the deletion, is what actually determines which condition applies. Always review the precise coordinates listed on your test report together with your physician.

3. Main Symptoms

The core features are developmental delay, mild-to-moderate intellectual disability, and distinctive facial characteristics, though how these present varies considerably from person to person. Based on reported cases, GARD lists the following as characteristic features.

• Developmental delay and intellectual disability: language and motor development are often delayed, and mild-to-moderate intellectual disability is common in reported cases.
• Hypotonia (low muscle tone): infants may feel notably floppy and struggle with feeding.
• Distinctive facial features: a flat nasal bridge, epicanthal folds, low-set ears, a small chin, a thin upper lip, ptosis (drooping eyelids), and strabismus have all been reported.
• Short stature: overall smaller body size is sometimes seen.
• Behavioral and psychiatric features: heightened anxiety, short attention span, attention-deficit/hyperactivity disorder, and epilepsy appear among reported cases.
• Other features: short fingers (brachydactyly), curved fingers (clinodactyly), and excessive drooling have also been noted.

Because the total number of documented cases is small, not every child will show all of these features. It is essential to look at each child’s own combination of symptoms and identify the support they need as they grow. For more on developmental characteristics, see our articles on NIPT and autism spectrum / developmental disorders and on what NIPT can and cannot tell you about intellectual disability.

4. Cause and Inheritance Pattern (De Novo vs. Autosomal Dominant)

Most cases arise as a sporadic, de novo event, though cases of familial transmission from a parent have also been reported.

De Novo (Sporadic) Cases

A copying error of this kind can occur by chance during the formation of sperm or eggs, or during cell division shortly after fertilization. It is not caused by anything in a mother’s diet, lifestyle, or work during pregnancy. In clinic, I always make a point of telling parents that there is nothing to blame themselves for.

Familial Transmission and Autosomal Dominant Inheritance

Because this condition is a structural chromosomal change, Orphanet classifies familial transmission as following a pattern consistent with autosomal dominant inheritance. If one parent carries the same deletion, there is roughly a 50% chance of passing it to each future child.

Some parents who carry the deletion have only very mild features and go undiagnosed. Once a child’s diagnosis is confirmed, chromosomal microarray testing of both parents can determine whether the deletion is de novo or inherited within the family — an important step for understanding the risk to future children accurately. Anyone with questions about a future pregnancy should seek genetic counseling from a certified clinical geneticist or genetic counselor.

5. Prenatal Diagnosis and Its Relationship to NIPT

The 11q22.2-q22.3 deletion is not covered by standard NIPT panels; it only becomes a candidate finding on an expanded panel that also screens for microdeletions.

Standard NIPT primarily screens for numerical chromosome changes — trisomy 21, 18, and 13. Some plans also include a limited number of relatively common microdeletions, such as 22q11.2 deletion syndrome, but an ultra-rare interstitial deletion like 11q22.2-q22.3 is often outside the scope of even those plans. Hiro Clinic NIPT offers an expanded panel covering 143 conditions, including microdeletions and microduplications, and a rare deletion of this kind can fall within the scope of that expanded testing.

It is important to keep in mind that NIPT is a non-definitive screening test, not a diagnosis. The NIPT guidelines published by the Japan Society of Obstetrics and Gynecology likewise state that NIPT results remain within the scope of screening and do not constitute a definitive diagnosis. A report from Japan’s Ministry of Health, Labour and Welfare expert panel on prenatal testing including NIPT similarly notes that expanded panels covering microdeletions have limitations in analytical and clinical validity.

If NIPT returns a positive finding for a microdeletion involving the 11q region, the first step is genetic counseling to understand what the result means. From there, couples work with their care team to decide whether to pursue a chromosomal microarray analysis (CMA) via amniocentesis. Because this is an ultra-rare condition, avoid drawing firm conclusions from a positive screening result alone, and work through the next steps with a specialist.

Early Infantile Epileptic Encephalopathy 4 (EIEE4)

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6. Steps to a Confirmed Diagnosis

Chromosomal microarray analysis (CMA) plays the central role in reaching a confirmed diagnosis.

Chromosomal Microarray Analysis (CMA)

This test can detect deletions as small as a few hundred kilobases to a few megabases — changes that traditional microscope-based karyotyping (G-banding) cannot see. It is performed on amniotic fluid before birth or on a blood sample after birth, and it maps precisely where a deletion begins and ends. That mapping is exactly what distinguishes this condition from Jacobsen syndrome, as discussed above.

FISH Testing and Parental Testing

Fluorescence in situ hybridization (FISH), which lights up a specific region of a chromosome, is sometimes used to confirm a diagnosis. Testing both parents’ blood alongside this can determine whether the deletion is de novo or was inherited within the family.

Postnatal Evaluation

After diagnosis, the care team builds a complete picture of the child’s condition through developmental assessment, a physical examination, and tumor-risk evaluation based on whether ATM and/or SDHD are affected. Regular, ongoing follow-up is essential throughout.

7. Treatment and Long-Term Tumor Screening

There is no treatment that restores the missing chromosomal material, but developmental support combined with long-term monitoring for SDHD-related tumors allows each child to grow at their own pace.

• Developmental support (early intervention): physical therapy (PT), occupational therapy (OT), and speech-language therapy (ST) help support motor, language, and daily-living skills.
• Behavioral support: when ADHD or heightened anxiety is prominent, care coordinated with child psychiatry or a developmental clinic is considered.
• Future tumor screening: when the deletion includes the SDHD gene, regular imaging and blood tests are reported to be recommended from adulthood onward to catch paraganglioma or pheochromocytoma early.
• Choosing an educational setting: families work with local education support centers to choose a setting — a special-needs school, a special-needs class, or a resource room — that fits the child’s needs.

Because the combination and severity of symptoms differ from child to child, there is no single fixed course this condition is guaranteed to follow. Pediatric neurology, clinical genetics, and oncology when needed all work together to build a support plan tailored to each child, one step at a time.

8. Outlook and Prognosis

Most reports describe mild-to-moderate intellectual disability, and quality of life largely depends on early intervention along with ongoing tumor screening into adulthood.

In reported cases, even deletions larger than 8 Mb have often been associated with relatively mild intellectual disability. At the same time, when the deletion includes the SDHD gene, continued screening for tumors into adulthood is essential.

Because so few cases have been documented, drawing firm conclusions about long-term outcomes remains difficult at this stage of research. What matters most is regular developmental evaluation, early detection through tumor screening, and the steady accumulation of day-to-day care — a realistic path toward preserving quality of life.

9. Support for Families and Considerations for Future Pregnancies

The isolation that comes with an ultra-rare condition can be significant, but genetic counseling, patient support groups, and public consultation services are all resources families can turn to.

It may be difficult to find another family nearby facing the same diagnosis. Even so, connections with other families affected by chromosomal rare diseases, and the specialized support genetic counseling provides, remain available. Day-to-day medical management is best left to physicians and early-intervention staff, while a family’s role, as I see it, is to celebrate each small step of a child’s growth together.

If you would like to learn more about other microdeletion syndromes, or chromosomal conditions that are often confused with one another, the following articles may help.

Xq28 Deletion Syndrome

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17q12 Deletion Syndrome

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If you are concerned about microdeletions in general, our article on the risks associated with tiny chromosomal changes may also help.

If you are considering NIPT for a future pregnancy, how far a plan’s microdeletion coverage extends will shape which option is right for you. If you are unsure which plan fits your situation, try our Plan Finder. Phone consultations are also available; feel free to call 0120-169-629 with any questions.

Frequently Asked Questions

Are 11q22.2-q22.3 microdeletion syndrome and 11q terminal deletion (Jacobsen syndrome) the same condition?

No, they are distinct conditions. This article covers an “interstitial deletion,” where only part of the mid-region of the long arm is lost, whereas Jacobsen syndrome is a “terminal deletion,” where the entire end of the chromosome is lost. The genes involved and the typical symptoms differ, so a chromosomal microarray analysis is used to confirm exactly which region is affected.

How common is this condition?

Orphanet classifies it as an ultra-rare condition with a global prevalence of fewer than 1 in 1,000,000 people. Because so few cases have been documented, a precise incidence rate has not yet been established.

Can NIPT detect this condition?

It is not typically included in standard NIPT panels; it may be identified on an expanded panel that also screens for microdeletions. Because NIPT is a non-definitive test, a positive finding needs to be confirmed with a diagnostic test such as amniocentesis.

Is this an inherited condition, and could it affect a future child?

Most cases occur as a sporadic, de novo event, and the recurrence risk for a future child is generally considered low. However, if either parent carries the same deletion, there is roughly a 50% chance of passing it on, so genetic counseling is recommended to clarify the risk.

What test confirms the diagnosis?

Chromosomal microarray analysis (CMA) is the central diagnostic test. It can detect fine deletions that traditional microscope-based testing would miss, and FISH testing or parental testing can be used to confirm the result as needed.

I’ve heard there may be a future cancer risk. Is that true?

When the deletion includes the SDHD gene, published research reports an increased possibility of paraganglioma or pheochromocytoma from adulthood onward. This does not apply to everyone; confirming the extent of the deletion and monitoring with regular imaging is what is recommended.

Medical supervision: Hiroshi Oka, MD, PhD — Director-General, Hiro Clinic (Fukumi-kai Medical Corporation), and Laboratory Director. Graduate of Keio University School of Medicine; licensed physician in both Japan and the United States. This article was prepared in line with Japan’s medical advertising guidelines, drawing on public and academic sources including GARD, Orphanet, the Japan Society of Obstetrics and Gynecology, Japan’s Ministry of Health, Labour and Welfare, and peer-reviewed literature. Because this is a rare condition with few documented cases, reported frequencies and figures vary across sources. Please discuss diagnosis and treatment decisions with your own physician.