distal trisomy 1p36

Distal trisomy 1p36 is a rare chromosomal anomaly syndrome caused by the partial duplication of the short arm of chromosome 1. The condition is characterized by borderline to mild intellectual disability, mild developmental delay, and distinct craniofacial features such as a sloping forehead, bitemporal narrowing, and blepharophimosis. Additional findings can include metopic craniosynostosis, growth retardation, microcephaly, and congenital heart malformations. Precise prevalence estimates are not well established, and the genetic basis is thought to result from a chromosomal duplication event rather than a single gene defect.

Individuals with distal trisomy 1p36 may present with mild developmental delays and borderline to mild intellectual disability. Characteristic facial dysmorphisms, including a sloping forehead, bitemporal narrowing, and blepharophimosis, are often observed along with metopic craniosynostosis. Other variable features can include growth retardation, microcephaly, large hands, syndactyly, supernumerary ribs, rectal stenosis, anterior displacement of the anus, and congenital heart defects such as atrial septal defect and patent ductus arteriosus. Not all individuals experience all features, and severity varies considerably.

Distal trisomy 1p36 is caused by a duplication of the terminal segment of the short arm of chromosome 1. The genetic basis is not linked to any single gene variant and is thought to result from a chromosomal rearrangement event that typically occurs sporadically. Since no specific inheritance pattern has been established, the precise causes remain under investigation. Families are encouraged to seek genetic counseling to discuss potential recurrence risks and implications for family planning.

Currently, management of distal trisomy 1p36 focuses on supportive care and symptom management rather than targeted treatments. Treatment plans are individualized and typically involve a multidisciplinary team addressing developmental needs, craniofacial concerns, cardiac anomalies, and other associated medical issues. Regular surveillance is an essential part of long‐term care to monitor for complications, and families are advised to discuss treatment options with their healthcare team. In addition, genetic counseling is recommended to help families understand the condition and its implications.

Outcomes for individuals with distal trisomy 1p36 vary widely, with clinical courses ranging from mild developmental challenges to more complex medical needs related to congenital anomalies. With current standards of care and early intervention, many affected individuals benefit from improvements in quality of life and may live into adulthood. Regular, multidisciplinary follow-up is important to manage emerging medical issues, and variability in severity means that each individual’s journey is unique. Outcomes described in medical literature continue to evolve as standards of care improve, and families often find it helpful to connect with pediatric specialists and genetic counselors.