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Potocki-Shaffer syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Potocki‑Shaffer syndrome

Potocki‑Shaffer syndrome is a rare genetic disorder caused by a deletion on chromosome 11p11.2, leading to distinctive skull abnormalities, bone tumors, and developmental delays.

Overview

Potocki‑Shaffer syndrome is a disorder that affects the development of the bones, brain, and other tissues. The signs and symptoms of Potocki‑Shaffer syndrome vary widely among affected individuals.

People with Potocki‑Shaffer syndrome have enlarged openings (foramina) in the parietal bones, which are the two bones that form the top and sides of the skull. Openings in the parietal bones are normal during fetal development, but they usually close before birth. In people with this condition, the parietal foramina are larger than normal and may remain open after birth. Affected individuals often have a wide, short skull (). Their head size may be normal or unusually small.

Most people with Potocki‑Shaffer syndrome have multiple noncancerous (benign) bone tumors called osteochondromas. In rare instances, these tumors become cancerous.

Other features of Potocki‑Shaffer syndrome include intellectual disabilities, recurrent seizures (epilepsy), and delayed development of speech and motor skills (such as sitting and walking).

Many people with Potocki‑Shaffer syndrome have distinctive facial features, such as a broad and tall forehead, a prominent bridge of the nose, a narrow distance between the nose and upper lip (a short philtrum), a short nose with a wide tip, and a downturned mouth.

Less commonly, Potocki‑Shaffer syndrome causes vision problems; additional skeletal abnormalities; and defects in the heart, kidneys, and urinary tract.

Frequency

Potocki‑Shaffer syndrome is a rare condition, although its exact prevalence is unknown. Fewer than 100 cases have been reported in the scientific literature.

Causes & Risk Factors

Potocki‑Shaffer syndrome is caused by a of genetic material from the short (p) arm of chromosome 11 at a position designated 11p11.2. Because of this change, Potocki‑Shaffer syndrome is also known as proximal 11p deletion syndrome. The term "proximal" means that the missing piece is near the center of the chromosome. The size of the deletion varies among affected individuals. Studies suggest that an individual would need a deletion of at least 2.1 million DNA building blocks (base pairs), also written as 2.1 megabases (Mb), to develop all of the features associated with the condition. The loss of multiple genes within the deleted region causes the signs and symptoms of Potocki‑Shaffer syndrome.

In particular, the deletion of the ALX4, PHF21A, and EXT2 genes is associated with several of the characteristic features of Potocki‑Shaffer syndrome. The ALX4 and PHF21A proteins are involved in regulating the activity of genes, particularly those that play a role in the development of the brain, skull, and face. The EXT2 gene provides instructions for making a protein that modifies another protein that helps control the formation and growth of bones.

The deletion of the ALX4 gene causes the enlarged parietal foramina found in people with this condition. In addition, the loss of the PHF21A gene is the cause of intellectual disabilities and distinctive facial features in affected individuals. The deletion of the EXT2 gene is associated with the development of multiple osteochondromas. The loss of additional genes in the deleted region likely contributes to the other features of Potocki‑Shaffer syndrome.

Learn more about the genes and chromosome associated with Potocki‑Shaffer syndrome

  • ALX4
  • EXT2
  • PHF21A
  • chromosome 11

Inheritance

Potocki‑Shaffer syndrome follows an autosomal dominant inheritance pattern, which means a deletion of genetic material from one copy of chromosome 11 is sufficient to cause the disorder. In some cases, an affected person inherits the chromosome with a deleted segment from . More commonly, the condition results from a deletion that (eggs and sperm) in a parent or during early fetal development. In these instances, affected people typically have no history of the disorder in their family.

Other Names for This Condition

  • Chromosome 11p11.2 deletion syndrome
  • P11pDS
  • Proximal 11p deletion syndrome
  • PSS

Additional Information & Resources

Frequently Asked Questions

Early clues include brief staring spells, sudden jerking of arms or legs, unexplained loss of awareness, or episodes of tongue biting. If a child has a new “daydream‑like” episode, unexplained falls, or a change in behavior, a neurologist should be consulted for EEG testing and possible medication adjustment.
Yes—early, intensive speech‑language therapy is beneficial. Initiating therapy as soon as the child shows any vocal attempts (often before 12 months of age) can improve outcomes. Therapy should be individualized, focusing on oral‑motor skills, auditory processing, and language modeling, and continued regularly (2–3 sessions per week) throughout early childhood.
Because malignant transformation is rare but possible, most clinicians recommend a clinical exam and imaging (usually X‑ray or MRI) every 12‑18 months, or sooner if the tumor becomes painful, rapidly enlarges, or develops a new hard area. Any sudden change should prompt immediate evaluation by an orthopedic oncologist.
Baseline echocardiography and renal ultrasound are advised at diagnosis. If results are normal, repeat cardiac evaluation every 2–3 years and renal imaging every 3–5 years, or sooner if symptoms such as shortness of breath, hypertension, or urinary abnormalities develop.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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