Jacobsen syndrome

Jacobsen syndrome, also known as 11q terminal deletion disorder or 11q deletion syndrome, is a rare chromosomal disorder caused by a partial deletion of the long arm of chromosome 11 (11q23-qter). The deletion typically ranges from 5 to 20 megabases in size and most cases arise de novo, though a small proportion are inherited from a parent carrying a balanced translocation. The syndrome affects multiple body systems and is characterized by a recognizable pattern of physical, developmental, and medical features. Key clinical features include pre- and postnatal growth retardation, intellectual disability of variable severity, distinctive facial features (skull abnormalities including trigonocephaly, hypertelorism, ptosis, broad nasal bridge, short nose, thin upper lip, and small jaw), and a characteristic bleeding disorder called Paris-Trousseau syndrome, which involves thrombocytopenia or pancytopenia due to abnormal platelet formation. Congenital heart defects occur in approximately 50-65% of affected individuals, with left-sided obstructive lesions such as hypoplastic left heart syndrome being particularly common. Other features may include eye abnormalities, hearing loss, kidney malformations, gastrointestinal problems, immunodeficiency, and skeletal anomalies. There is no cure for Jacobsen syndrome, and management is multidisciplinary and symptom-based. Treatment may include surgical correction of congenital heart defects, platelet transfusions for bleeding complications, early intervention programs, speech and occupational therapy, and regular monitoring of growth, development, and organ function. Cardiac complications and bleeding disorders are the most significant contributors to morbidity and mortality. With appropriate medical management and supportive care, many individuals survive into adulthood, though they typically require ongoing support for intellectual disability and associated medical conditions.

Common questions about Jacobsen syndrome