9p Partial Trisomy Syndrome C0265428
A chromosomal condition involving an extra copy of part of chromosome 9. It can cause distinctive facial features, developmental delays, and various medical issues. Management is supportive and focuses on addressing individual symptoms.
Key facts at a glance
- ICD-10
- Q89.9
- ICD-11
- LA00.0
- Body system
- congenital
- Severity
- moderate
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Warning signs - seek immediate care
Congenital Heart Defects
Structural heart problems present at birth, including ventricular septal defects, atrial septal defects, or other cardiac malformations.
URGENT: If symptoms of heart failure such as difficulty breathing, poor feeding, or bluish skin appear, seek immediate medical attention.
Seizures
Recurrent seizure episodes resulting from abnormal electrical activity in the brain.
URGENT: Any first-time seizure requires immediate emergency medical evaluation.
Developmental Delay
(constitutional)Significant delays in reaching developmental milestones such as sitting, walking, and speaking compared to typical children of the same age.
Frequency: 90-100% of patients
Growth Retardation
(constitutional)Slowed growth in both height and weight, often noticeable in infancy and continuing through childhood.
Frequency: 80-90% of patients
Distinctive Facial Features
(facial)Characteristic facial appearance including widely spaced eyes, flat nasal bridge, prominent forehead, and abnormal ear positioning.
Frequency: 90-100% of patients
Hypotonia
(neurologic)Reduced muscle tone resulting in floppy limbs and difficulties with motor activities and posture.
Frequency: 75-85% of patients
Hand Abnormalities
(musculoskeletal)Long slender fingers, clinodactyly (inward curving of fingers), or thumb anomalies such as broad thumbs or thumb duplication.
Frequency: 60-70% of patients
Genital Abnormalities
(genitourinary)Underdeveloped genitalia, undescended testes in males, or abnormal vaginal development in females.
Frequency: 50-60% of patients
Dental Anomalies
(dental)Delayed tooth eruption, missing teeth, abnormally shaped teeth, or overcrowded teeth.
Frequency: 50-60% of patients
Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Growth and endocrine assessment
Regular monitoring of growth velocity, endocrine function, and puberty progression given common growth abnormalities in this syndrome.
Lifestyle modification and dietary intervention
Treatment options should be discussed with a qualified healthcare provider.
Rehabilitation for hand and limb abnormalities
Specialized therapy addressing hand abnormalities, joint contractures, and skeletal issues common in 9p partial trisomy, including splinting and functional exercises.
Additional treatment options
Educational and behavioral support
Individualized education plans and behavioral interventions to address intellectual disability, learning challenges, and behavioral concerns associated with the syndrome.
psychologicalOrthopedic intervention for skeletal abnormalities
Surgical procedures to address significant skeletal anomalies, hand abnormalities, or spinal deformities when conservative management is insufficient.
surgicalMultidisciplinary care coordination
Coordination among genetics, orthopedics, endocrinology, and developmental specialists to ensure comprehensive care addressing all aspects of the syndrome.
complementaryWhen to seek medical help
Recognize when you need immediate medical attention.
Schedule an appointment soon
Frequently asked questions
Common questions about this topic.
What is 9p Partial Trisomy Syndrome C0265428?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Stankiewicz P, Lupski JR. Molecular genetics of 9p-trisomy syndrome. Clin Genet. 2002 Aug;62(2):110-6.
Jones KL, Jones MC, del Campo Casanelles M. Smith's Recognizable Patterns of Human Malformation. 7th ed. Elsevier; 2013.
Mendoza-Ferreira N, Hoyer J, Zweier C. 9p Partial Trisomy. In: Adam MP, et al., editors. GeneReviews. University of Washington; 2020.
Chiurazzi P, Novelli A, Giardina D, et al. Trisomy 9p: a review of the phenotype and genotype in 45 cases. Clin Dysmorphol. 2000 Jul;9(3):195-200.
Lurie IW, Wulfsberg EA. On the heterogeneity of the 9p+ syndrome. Ann Genet. 1994;37(2):83-9.
Barisic I, McManus MP, Ceylaner S, et al. Clinical and genetic aspects of 9p partial trisomy: a case report and review of the literature. Clin Genet. 2008 Aug;74(2):168-70.
American College of Medical Genetics and Genomics. Clinical Genetics: A Guide to Genetic Testing and Counseling. ACMG; 2019.
Orphanet. Trisomy 9p. Orphanet Rare Disease Database. 2021.
Fryns JP, Bulck H, Lagae L, et al. Trisomy 9p: cytogenetic studies and clinical follow-up. Am J Med Genet A. 2003 Jul 15;119A(2):188-91.
Schinzel A. Catalogue of Unbalanced Chromosome Aberrations in Man. 2nd ed. Walter de Gruyter; 2001.
Medication Comparisons
Compare medications used to treat 9p Partial Trisomy Syndrome C0265428. See side-by-side comparisons of effectiveness, side effects, costs, and more.
View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 26, 2026. · Read our editorial policy