Potocki-Shaffer syndrome is a rare genetic condition caused by the loss of a small piece of chromosome 11 and is also known as chromosome 11p11.2 deletion syndrome and DEFECT11 syndrome. The condition typically involves a distinctive combination of skull and bone changes alongside developmental differences, although the exact combination of features varies from person to person. Because the underlying deletion can vary in size, some individuals experience a broader range of symptoms while others have a milder presentation. Only a limited number of individuals with Potocki-Shaffer syndrome have been described in the medical literature, making it an extremely rare contiguous gene deletion syndrome.
What Causes It?
Potocki-Shaffer syndrome results from the deletion of a specific region on the short arm of chromosome 11, known as 11p11.2. Several genes within this deleted region contribute to the condition’s characteristic features. Loss of the ALX4 gene is associated with enlarged parietal foramina, openings in the skull bones that normally close during development. Loss of the EXT2 gene is associated with multiple osteochondromas (noncancerous bone growths) that develop near the ends of long bones. Loss of PHF21A has been linked to developmental delay, intellectual disability, and characteristic craniofacial features. In some individuals, the deletion extends beyond the typical Potocki-Shaffer syndrome region and includes additional genes, which may contribute to a broader range of medical findings.
Is It Inherited?
Potocki-Shaffer syndrome follows an autosomal dominant inheritance pattern because the deletion affects one copy of chromosome 11. However, most cases occur as a new (de novo) genetic change, meaning the deletion develops for the first time in the affected child and is not inherited from either parent. Less commonly, the deletion may be inherited from an affected parent or result from an unbalanced chromosome rearrangement inherited from a parent who carries a balanced rearrangement. After diagnosis, genetic counseling is recommended. Testing the parents may help determine whether the deletion occurred spontaneously or was inherited and can provide more accurate information about recurrence risk in future pregnancies.
What Are the Main Symptoms?
Two hallmark features of Potocki-Shaffer syndrome are multiple osteochondromas and enlarged parietal foramina, although not every individual develops both findings. Osteochondromas usually appear during childhood and may cause pain or restricted movement, although malignant transformation is uncommon. Enlarged parietal foramina are openings in the parietal bones of the skull rather than persistent “soft spots.” A craniofacial or neurosurgical specialist may monitor these findings when clinically appropriate. Beyond these hallmark features, many individuals also have craniofacial differences such as a prominent forehead, brachycephaly, and a narrow nasal bridge. Developmental delay and intellectual disability are common, although their severity varies considerably. Some individuals also experience vision problems, hearing loss, or, less commonly, heart, kidney, or urinary tract differences.
How Is It Diagnosed?
Diagnosis typically begins with a physical examination and review of characteristic skeletal and developmental findings. Chromosomal microarray testing usually confirms the diagnosis by identifying the chromosome 11 deletion. The size of the deletion and the genes involved help guide medical evaluation and genetic counseling. Imaging studies, including skull X-rays or a skeletal survey, may help evaluate parietal foramina and osteochondromas. Vision and hearing assessments, developmental evaluation, and additional specialist assessments may also be recommended based on the individual’s clinical findings.
Managing the Condition
There is currently no cure for Potocki-Shaffer syndrome, so management focuses on monitoring associated medical conditions and supporting development. Orthopedic specialists monitor osteochondromas over time, and some may require surgical removal if they cause pain, limit movement, or compress nearby structures. Speech, occupational, and physical therapy may support communication, motor development, and daily living skills. Regular hearing and vision evaluations can identify concerns that may affect communication, development, or learning. A multidisciplinary team, including genetics, orthopedics, developmental specialists, and other specialists as needed, can help coordinate care.
Living With This Condition
Long-term outcomes vary considerably because the condition affects each person differently. Some individuals require lifelong medical and developmental support, while others have milder symptoms. Regular follow-up allows healthcare providers to monitor bone growth, development, hearing, vision, and other medical concerns over time. Families may also benefit from connecting with rare disease or chromosome disorder support organizations for educational resources and peer support.
Medical Disclaimer
This article is intended for educational purposes only and should not replace professional medical advice, diagnosis, or treatment. If you have questions about your child’s health or development, consult a qualified healthcare provider or clinical geneticist.
