OBSOLETE: Uniparental disomy of chromosome 11

Uniparental disomy of chromosome 11 (UPD 11) is an obsolete Orphanet entry that previously referred to a chromosomal anomaly in which both copies of chromosome 11 (or a segment of it) are inherited from a single parent rather than one from each parent. This concept is not itself a standalone disease but rather a genetic mechanism that can underlie specific clinical conditions depending on which parent contributes both copies and which chromosomal region is involved. The most clinically significant form is paternal uniparental disomy of chromosome 11p15, which is a well-recognized cause of Beckwith-Wiedemann syndrome (BWS), characterized by overgrowth, macroglossia (enlarged tongue), abdominal wall defects (such as omphalocele), organomegaly, neonatal hypoglycemia, and an increased risk of embryonal tumors including Wilms tumor and hepatoblastoma. Maternal UPD of chromosome 11 has been associated with features overlapping with Silver-Russell syndrome, including intrauterine and postnatal growth restriction. Because this Orphanet entry (263034) is designated as obsolete, patients and clinicians are directed to the specific syndrome entries — primarily Beckwith-Wiedemann syndrome (Orphanet: 116) for paternal UPD 11p15 or Silver-Russell syndrome (Orphanet: 813) for maternal UPD 11 — for current clinical guidance. The affected body systems vary depending on the resulting phenotype but commonly include the musculoskeletal system, endocrine system, kidneys, liver, and abdominal organs. Management is syndrome-specific and may include monitoring blood glucose in the neonatal period, surgical correction of abdominal wall defects, tumor surveillance protocols (particularly for Wilms tumor and hepatoblastoma in BWS), and growth support in cases of growth restriction. Genetic counseling is recommended for affected families, as the recurrence risk depends on the underlying mechanism of UPD.

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