12q15q21 1 Microdeletion Syndrome C4518344
A rare chromosomal deletion affecting a portion of chromosome 12. Presentation varies and may include developmental concerns and medical issues. Treatment addresses specific symptoms with a multidisciplinary approach.
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 defect
Structural abnormalities of the heart present at birth, including septal defects or valve abnormalities.
Seek immediate medical attention if symptoms of heart failure develop such as rapid breathing, poor feeding, or bluish skin discoloration.
Kidney abnormalities
Structural kidney anomalies such as renal hypoplasia, hydronephrosis, or missing kidneys.
Seek prompt medical evaluation if urinary symptoms, flank pain, or fever occur.
Developmental delay
(neurologic)Delays in reaching developmental milestones such as sitting, walking, and talking during early childhood.
Frequency: 90-100% of patients
Prenatal growth retardation
(constitutional)Reduced fetal growth during pregnancy leading to low birth weight and small size for gestational age.
Frequency: 80-90% of patients
Intellectual disability
(neurologic)Impaired cognitive functioning affecting learning, problem-solving, and adaptive skills.
Frequency: 70-80% of patients
Feeding difficulties
(gastrointestinal)Problems with feeding, including poor sucking, gagging, or difficulty with solid foods in infants.
Frequency: 60-70% of patients
Postnatal growth failure
(constitutional)Failure to gain weight and grow at the expected rate during childhood despite adequate nutrition.
Frequency: 60-70% of patients
Speech and language delay
(neurologic)Delayed onset of speech and language development, often with articulation difficulties.
Frequency: 70-80% of patients
Skeletal abnormalities
(musculoskeletal)Bone and joint issues including scoliosis, joint laxity, or abnormal bone development.
Frequency: 20-30% 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
Comprehensive multi-specialty surveillance
Coordinated care with genetics, cardiology, gastroenterology, and developmental specialists to monitor and manage the variable phenotype of 12q15q21-1 microdeletion syndrome.
Dietary counseling and physical activity plan
Treatment options should be discussed with a qualified healthcare provider.
Feeding and gastrointestinal management
Specialized feeding programs addressing oral motor dysfunction, GERD management, and nutritional support for individuals with feeding difficulties.
Additional treatment options
Motor development intervention
Early intervention services providing physical and occupational therapy to promote motor milestones and address hypotonia or motor planning difficulties.
physical_therapyBehavioral and emotional support
Behavioral therapy and emotional support addressing anxiety, social difficulties, and behavioral regulation challenges that may occur with this condition.
psychologicalCorrective procedures as needed
Surgical intervention for associated structural anomalies such as cleft palate, skeletal abnormalities, or other congenital defects when clinically indicated.
surgicalWhen 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 12q15q21 1 Microdeletion Syndrome C4518344?
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.
Online Mendelian Inheritance in Man. 12q15q21.1 microdeletion syndrome. OMIM #617788.
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. American Journal of Human Genetics.
Leduc-Rogers G, Baumann A, Delahaye C, et al. 12q15q21.1 microdeletion syndrome: report of a new case and review of the literature. European Journal of Medical Genetics.
DECIPHER Database. 12q15q21.1 microdeletion syndrome. Wellcome Sanger Institute.
Kearney HM, Thorland EC, Brown KK, et al. American College of Medical Genetics standards and guidelines for interpretation and reporting of postnatal constitutional copy number variants. Genetics in Medicine.
GeneReviews. 12q24.31 Microdeletion Syndrome. University of Washington.
Orphanet. 12q15q21.1 microdeletion syndrome. Rare Disease Database.
Rosenfeld JA, Coe BP, Eichler EE, et al. Estimates of penetrance for pathogenic copy-number variants across multiple phenotypes. Genetics in Medicine.
Medication Comparisons
Compare medications used to treat 12q15q21 1 Microdeletion Syndrome C4518344. 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