7q11.23 Distal Deletion Syndrome

Seeing the diagnosis “distal 7q11.23 deletion syndrome” for the first time, you may feel unsettled by such an unfamiliar term.

Here is the conclusion up front: this condition is a distinct, rare genetic disorder in which the region deleted on chromosome 7’s long arm at 11.23 sits farther toward the end (distal) than the region responsible for the well-known Williams syndrome. Epilepsy, developmental delay, and behavioral traits are the central features, while the cardiac disease and distinctive facial appearance typical of Williams syndrome are not necessarily prominent.

This article walks through the underlying chromosomal change, how it differs from Williams syndrome, its symptoms, inheritance pattern, its relationship to prenatal diagnosis and NIPT, and treatment and support options — all based on information from public health authorities and peer-reviewed literature. Rather than being swayed by scattered pieces of information, let’s work through this one step at a time.

1. What Is Distal 7q11.23 Deletion Syndrome? (The Underlying Chromosomal Change)

This condition occurs when a person is born missing a segment of chromosome 7’s long-arm 11.23 region that lies closer to the telomere (chromosome end) than the region responsible for Williams syndrome. Medically, it is called “distal 7q11.23 microdeletion syndrome.”

The extent of the deletion varies from case to case. Published reports describe cases in which a region of roughly 0.8–1.2 Mb — containing the HIP1 and YWHAG genes — is missing. This region is thought to contain somewhere between a dozen and about 20 genes.

The Genetic and Rare Diseases Information Center (GARD), run by the U.S. National Institutes of Health (NIH), describes this condition as a genetic disorder caused by a change in the number or structure of chromosomes. Case reports in Japanese remain limited, and the exact prevalence has not been firmly established.

The Difference Between “Proximal” and “Distal”

Within the 7q11.23 region, the genes involved — and the conditions they cause — differ depending on whether the deletion is toward the center (proximal) or the end (distal).

• Proximal deletion: A deletion of about 1.5–1.8 Mb that includes the elastin gene (ELN) — this is the cause of Williams syndrome.
• Distal deletion: A region including HIP1, YWHAG, and other genes is missing — this is the “distal 7q11.23 deletion syndrome” discussed in this article. Because a different set of genes is lost compared with the proximal deletion, the central symptoms differ as well.

Even at the same “address” on chromosome 7 — the long arm’s q11.23 region — a different “house number” results in an entirely different condition. It’s worth keeping this positional relationship in mind first. For a broader overview of 7q deletions as a whole, see our article on chromosome 7 long-arm deletion syndrome (7q deletion).

2. How It Differs From Williams Syndrome

Because both conditions share the name “7q11.23,” they are easily confused — but distal deletion syndrome and Williams syndrome are separate conditions with different causative genes and different core symptoms. The table below summarizes the differences.

Comparison Point	Williams Syndrome (Proximal 7q11.23 Deletion)	Distal 7q11.23 Deletion Syndrome
Location of deletion	Central (proximal) part of 7q11.23	End (distal) part of 7q11.23
Key causative genes	Elastin gene (ELN) and roughly 20 others	HIP1, YWHAG, and others
Cardiovascular features	Frequently involves heart disease, such as supravalvular aortic stenosis	Cardiac disease is not considered an essential feature
Facial features	A distinctive facial appearance (so-called “elfin facies”) is well recognized	A distinctive facial appearance is not a consistent finding
Neurological/behavioral	Overly sociable personality, difficulty with visuospatial tasks, and more	Epilepsy, developmental delay, autism spectrum tendencies, and more
Frequency of epilepsy	Rare	Reported in about 80% of cases in one study

Williams syndrome is known for cardiac disease and a distinctive facial appearance. Distal deletion syndrome, by contrast, is most often reported with epilepsy and developmental/behavioral traits as its core features. Japan’s Center for Intractable Disease Information has a page describing Williams syndrome as a nationally designated intractable disease (Japanese-language page), which can be a useful reference for the proximal-side symptoms.

Orphanet, Europe’s rare disease database, also lists distal 7q11.23 deletion syndrome as an independent condition separate from Williams syndrome (Orphanet entry). If you see “7q11.23” on a diagnostic report, be careful not to assume it automatically means the same thing as Williams syndrome.

3. Key Symptoms

Epilepsy, developmental delay, and behavioral traits form the core of this condition, and severity varies widely from person to person. A U.S. research group studied 26 individuals across 10 families, and their findings on how symptoms present are summarized below.

Symptom / Trait	Approximate Reported Frequency
Epilepsy (absence seizures, myoclonic seizures, infantile spasms, and others)	About 80% of individuals studied
Severe developmental delay, or autism spectrum tendencies	Just under 60% of individuals studied
Mild intellectual developmental disorder (intellectual disability)	Just under 20% of individuals studied
Learning difficulties (without major delay in intellectual development)	Just under 20% of individuals studied
No developmental concerns noted	Just under 10% of individuals studied

On the behavioral side, reported traits include heightened anxiety, sensory sensitivity, hyperactivity, impulsivity, and difficulty sustaining attention. Self-injurious behavior or low mood have also been reported in rare cases. As for epilepsy, the seizure type — absence seizures, focal seizures, and others — also varies from person to person.

As a neurological complication, Chiari malformation — in which part of the cerebellum (the cerebellar tonsils) sits lower than normal — has also been reported. Its frequency and severity vary, and it is not a finding shared by everyone with this condition. This information draws on GARD and the research paper that first identified HIP1 and YWHAG as the genes involved.

For more on the relationship between intellectual disability and developmental traits, our article on NIPT and intellectual disability in numbers covers overall trends across chromosomal conditions. For how autism spectrum disorder fits into this picture, see our article on NIPT and developmental disorders/autism as well.

4. Cause and Inheritance Pattern (De Novo vs. Familial Transmission)

Most cases arise from a spontaneous (de novo) mutation, though in rare instances the deletion is inherited from a parent — meaning the implications for a future child depend on the specific family.

De Novo (Spontaneous) Cases

A copy error of this kind can occur by chance during the formation of sperm or egg cells, or during early cell division shortly after fertilization. It is not caused by anything a mother eats, does, or is exposed to during pregnancy. There is no reason to blame yourself.

Familial Transmission and Dominant Inheritance

Distal 7q11.23 deletion syndrome follows an autosomal dominant pattern of inheritance (a single copy inherited from one parent is enough to cause the condition). Some reported families include cases where a mother passed the deletion to multiple children. Notably, even within the same family sharing the identical deletion, whether epilepsy occurred — and how severe symptoms were — varied from person to person.

This reflects variable penetrance and expressivity: even with the identical genetic change, outcomes range from individuals with almost no symptoms to children with pronounced epilepsy and developmental delay.

When the deletion is de novo, the recurrence risk for a future pregnancy is generally considered low. However, if either parent carries the same deletion — even mildly or without symptoms — there is approximately a 50% chance of passing it on to a future child. Parental chromosomal microarray testing is useful for clarifying your family’s exact inheritance pattern.

In my own clinical experience, I have met parents of children with rare chromosomal conditions like this one who come to ask about a future pregnancy. I have found that simply knowing the parents’ own test results often makes it easier to picture what comes next. If you are concerned about the risk to a future child, I would encourage you to consider genetic counseling with a certified clinical geneticist or genetic counselor.

5. Prenatal Diagnosis and Its Relationship to NIPT

The distal 7q11.23 deletion is not included in standard NIPT panels. It is an extremely rare region that only becomes a candidate on expanded panels that screen for microdeletions.

A standard basic NIPT mainly looks for numerical chromosomal changes — trisomy 21, 18, and 13. Some plans also include relatively common microdeletions, such as 22q11.2 deletion syndrome (DiGeorge syndrome). Whether an extremely rare region like the distal 7q11.23 deletion is included, however, depends on the testing company and the specific plan.

At Hiro Clinic NIPT, we sometimes receive questions such as, “What should I do if an unfamiliar region shows up as a possibility on a microdeletion-inclusive test?” The first thing to understand is that NIPT is, first and foremost, a non-diagnostic screening test.

The Japan Society of Obstetrics and Gynecology (JSOG) publishes guidelines on NIPT (Japanese-language PDF). These guidelines likewise state that NIPT results remain within the scope of a screening — that is, non-diagnostic — test. A definitive diagnosis requires an invasive test such as amniocentesis. It is also known that as a microdeletion panel’s scope broadens, the positive predictive value — the proportion of positive results that reflect an actual condition — tends to decline.

If NIPT returns a positive finding for a microdeletion involving the 7q11.23 region, the typical next steps are as follows: first, genetic counseling to clarify what the result means, followed by a decision about whether to pursue chromosomal microarray analysis (CMA) via amniocentesis. There is no need to rush to a conclusion — work through each step together with a specialist.

6. Steps to a Definitive Diagnosis

Chromosomal microarray (CMA) — a high-resolution genetic test — plays the central role in reaching a definitive diagnosis.

Chromosomal Microarray (CMA)

CMA can detect deletions and duplications on the scale of a few hundred kilobases to several megabases — changes too small to be seen with conventional microscopic chromosome analysis (G-banding). It reveals precisely where a deletion begins and ends, including whether it includes the HIP1 and YWHAG genes.

FISH Testing and Parental Testing

FISH (fluorescence in situ hybridization) testing, which lights up a specific region for confirmation, is sometimes used to support the diagnosis. Testing the parents’ blood can also determine whether the deletion is de novo or was inherited within the family.

Postnatal Evaluation

After diagnosis, an EEG to evaluate for epilepsy, developmental assessments, and — when needed — brain imaging (to check for Chiari malformation, for example) are combined to build a complete picture of the child’s condition.

7. Treatment and Support

There is currently no treatment that restores the missing chromosomal segment. However, symptom-focused care and developmental therapy can support each child’s own path of growth.

• Epilepsy management: Working with a pediatric neurologist to select anti-seizure medication matched to the seizure type, with ongoing follow-up via regular EEGs.
• Developmental therapy: Physical therapy (PT), occupational therapy (OT), and speech-language therapy (ST) support motor skills, language, and daily living skills.
• Behavioral and psychological support: When autism spectrum tendencies, hyperactivity, or significant anxiety are present, behavioral therapy and counseling with a psychologist are used together.
• Choosing an educational setting: Options such as special-needs schools, special-needs classes, or resource rooms are selected in consultation with local education support centers, based on the child’s individual needs.

Because the combination and severity of symptoms differ from child to child, there is no single fixed course that “always” happens with this condition. A support plan is built gradually, together with your child’s pediatric neurologist and developmental therapy team, and tailored to your child specifically.

8. Outlook and Prognosis

Outcomes range widely — from individuals with no notable developmental delay to those who need long-term support — and early developmental therapy together with good epilepsy control strongly shapes quality of life.

Published case series include a meaningful number of individuals with no developmental concerns at all, alongside others who have epilepsy or significant developmental delay. This variation is thought to reflect differences in the exact size of the deletion, which genes are involved, and individual differences in penetrance.

Given the current state of research, it is not yet possible to state a definitive long-term outlook. Day-to-day quality of life tends to depend heavily on whether seizures are well controlled with medication and how early developmental therapy begins.

9. Support for Families and Thinking About a Future Pregnancy

The isolation that comes with a rare disease diagnosis can be significant, but there are several places to turn for support — genetic counseling, family support groups, and public consultation services among them.

You may not find another family nearby whose child has the exact same condition. Even so, you can connect with other families affected by rare chromosomal conditions and draw on the specialized support of genetic counseling. Medical management can be left to your child’s doctors and therapy team — a family’s role, I believe, is to notice and celebrate each small step of your child’s own progress.

If you’d like to learn about other microdeletion syndromes, the articles below may also help.

Xq28 Deletion Syndrome

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20p13 Microdeletion Syndrome

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If microdeletions in general are a concern, our article on the risks associated with subtle chromosomal changes may help. For more on developmental individuality, see our article on what NIPT can reveal about intellectual disability as well.

If you’re considering NIPT for a future pregnancy, how far microdeletion coverage extends will vary by plan. If you’re not sure which plan is right for you, try our Plan Finder. Phone consultations are also welcome — please feel free to call us at 0120-169-629.

Frequently Asked Questions

Are distal 7q11.23 deletion syndrome and Williams syndrome the same condition?

No, they are different conditions. Both involve a deletion in the 7q11.23 region of chromosome 7’s long arm, but Williams syndrome involves the proximal (central) portion, while the condition discussed in this article involves the distal (far end) portion. The genes involved and the primary symptoms differ between the two.

Does this condition involve heart problems?

Unlike Williams syndrome, cardiac disease is not considered an essential feature. The main features are epilepsy and developmental/behavioral traits. That said, because individual variation exists, a full physical examination after birth is used to check overall health, including the heart.

Can NIPT detect the distal 7q11.23 deletion?

It is not usually included in a standard NIPT panel. It’s an extremely rare region that may appear as a candidate only on expanded panels covering microdeletions. Because NIPT is a screening (non-diagnostic) test, a positive finding needs to be confirmed with a diagnostic test such as amniocentesis.

Is this an inherited condition? Could it affect a future child?

Most cases arise from a spontaneous (de novo) mutation, and the recurrence risk for a future child is generally considered low. However, if either parent carries the same deletion, even mildly, there’s about a 50% chance of passing it on — this is worth confirming through genetic counseling.

What test provides a definitive diagnosis?

Chromosomal microarray (CMA) is the primary diagnostic test. It can detect subtle deletions that conventional microscopic testing would miss, and FISH testing or parental testing may be used for additional confirmation when needed.

How common is epilepsy in this condition?

In a study of 26 individuals from 10 families, epilepsy was reported in about 80% of participants. Seizure types varied — including absence seizures and myoclonic seizures — and severity differed from person to person.

Medical supervision: Dr. Hiroshi Oka — Director-in-Chief and Lab Director, Hiro Clinic (Fukumikai Medical Corporation). A graduate of Keio University School of Medicine, Dr. Oka holds a Ph.D. in Medicine and has passed the national medical licensing examinations of both Japan and the United States. He is one of the few physicians in Japan to hold laboratory director credentials. This article was prepared in line with Japan’s medical advertising guidelines, drawing on public and academic sources including the NIH Genetic and Rare Diseases Information Center (GARD), Orphanet, Japan’s Center for Intractable Disease Information, the Japan Society of Obstetrics and Gynecology (JSOG), and peer-reviewed research literature. Reported frequencies and figures vary somewhat between sources; please consult your physician for decisions about diagnosis and treatment.