3q26q27 Microdeletion Syndrome C4755255
A genetic disorder from missing genetic material spanning 3q26 to 3q27, associated with developmental delays, growth concerns, and various medical features.
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
Seizures
Recurrent episodes of uncontrolled electrical activity in the brain causing convulsive movements or altered consciousness.
Seek emergency care immediately if a seizure lasts more than 5 minutes or if multiple seizures occur in 24 hours.
Congenital heart defect
Structural abnormality of the heart present at birth, such as ventricular septal defect or atrial septal defect.
Cardiac evaluation is essential; seek immediate care if symptoms like rapid breathing, poor feeding, or bluish skin appear.
Global developmental delay
(neurologic)Significant delays in reaching developmental milestones such as sitting, crawling, and walking compared to typical children of the same age.
Frequency: 90-100% of patients
Intellectual disability
(neurologic)Reduced cognitive functioning affecting learning, problem-solving, and adaptive skills of varying severity.
Frequency: 85-95% of patients
Failure to thrive
(constitutional)Inadequate weight gain and growth velocity resulting in falling below standard growth percentiles for age.
Frequency: 70-85% of patients
Microcephaly
(neurologic)Abnormally small head circumference present at birth or developing in early infancy due to reduced brain growth.
Frequency: 80-90% of patients
Speech and language delay
(neurologic)Significant delay in speech development and expressive language abilities, often with delayed or absent verbal communication.
Frequency: 85-95% of patients
Distinctive facial features
(constitutional)Characteristic facial appearance including micrognathia (small jaw), hypertelorism (wide-set eyes), and other subtle dysmorphic features.
Frequency: 60-80% of patients
Feeding difficulties
(gastrointestinal)Problems with feeding, swallowing, or weight gain due to oral motor dysfunction or gastrointestinal issues.
Frequency: 40-60% of patients
Genitourinary abnormalities
(genitourinary)Structural abnormalities of the kidneys, bladder, or reproductive organs, including renal malformations or hypospadias.
Frequency: 15-25% 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
Behavioral and nutritional therapy
Treatment options should be discussed with a qualified healthcare provider.
Neurodevelopmental surveillance
Systematic monitoring of developmental milestones, growth parameters, and neurological function with regular screening for autism spectrum features and intellectual disability.
Early intervention services
Coordinated early intervention services including speech therapy, occupational therapy, and developmental support tailored to individual needs.
Additional treatment options
Symptomatic medication management
Pharmacological treatment as needed for specific symptoms such as seizures, attention difficulties, or mood regulation issues under specialist supervision.
medicationFamily support and education programs
Access to support groups, parent education, and family resources to help manage care demands and improve quality of life.
complementaryCardiac evaluation and monitoring
Echocardiogram and ongoing cardiac monitoring to screen for congenital heart defects commonly associated with this chromosomal region.
procedureWhen 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 3q26q27 Microdeletion Syndrome C4755255?
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.
Lacassie Y, Brown W, Ledbetter DH, Magnusson M,Strong L, et al. Chromosome 3q26-q27 deletions: phenotype and molecular analysis. Am J Hum Genet. 1993;53(2):456
OMIM. 3q26q27 microdeletion syndrome. Online Mendelian Inheritance in Man.
Mandel M, Shinawi M. Cytogenetic and molecular characterization of 3q26.3 microdeletions: genotype-phenotype correlation. Am J Med Genet A. 2018;176(5):1099-1108.
Jones KL, Jones MC, del Campo Casanelles. Smith's Recognizable Patterns of Human Malformation. 8th ed. Elsevier; 2022.
American College of Medical Genetics and Genomics. Clinical Cytogenetics Guidelines for Chromosomal Microarray Analysis. Genet Med. 2021;23(9):1583-1590.
Coe BP, Witherspoon K, Rosenfeld JA, et al. Refining analyses of copy number variation identifies specific genes associated with developmental delay. Nat Genet. 2014;46(10):1063-1071.
Database of Genomic Variants. 3q26q27 microdeletion region. DGV.
Zhang F, Gu W, Hurles ME, Lupski JR. Copy number variation in human health, disease, and evolution. Annu Rev Genomics Hum Genet. 2009;10:451-481.
American Academy of Pediatrics. Genetic Testing and Screening in the Era of Precision Medicine. Pediatrics. 2020;145(6):e20201761.
Miller DT, Adam MP, Aradhya S, et al. Consensus statement: chromosomal microarray is a first-tier clinical diagnostic test for individuals with developmental disabilities or congenital anomalies. Am J Hum Genet. 2010;86(5):749-764.
Medication Comparisons
Compare medications used to treat 3q26q27 Microdeletion Syndrome C4755255. 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 20, 2026. · Read our editorial policy