Short answer · Medically reviewed summary · Last updated: 2026-05-08
Megalencephaly-Capillary Malformation-Polymicrogyria Syndrome (MCAP) does not currently have a unique, dedicated ICD-10 or ICD-9 code. Clinicians typically use "Q04.8" (Other specified congenital malformations of brain) in ICD-10 or "742.8" (Other specified anomalies of brain) in ICD-9 to classify the neurological manifestations of MCAP. Why does Megalencephaly-Capillary Malformation-Polymicrogyria Syndrome lack a specific code? Because MCAP is a rare, complex overgrowth disorder, it is often categorized under broader neurological or vascular malformation codes.
ICD10 code of Megalencephaly Capillary Malformation Polymicrogyria Syndrome (mcap) and ICD9 code
ICD-10 and ICD-9 codes for Megalencephaly Capillary Malformation Polymicrogyria Syndrome (mcap), with classification details for clinicians, coders and patients.
Megalencephaly-Capillary Malformation-Polymicrogyria Syndrome (MCAP) does not currently have a unique, dedicated ICD-10 or ICD-9 code. Clinicians typically use "Q04.8" (Other specified congenital malformations of brain) in ICD-10 or "742.8" (Other specified anomalies of brain) in ICD-9 to classify the neurological manifestations of MCAP.
Why does Megalencephaly-Capillary Malformation-Polymicrogyria Syndrome lack a specific code?
Because MCAP is a rare, complex overgrowth disorder, it is often categorized under broader neurological or vascular malformation codes. Rare diseases like Megalencephaly-Capillary Malformation-Polymicrogyria Syndrome are frequently grouped into "other specified" categories because they involve multiple organ systems, including the brain, skin, and limbs, making a single, highly specific code difficult to assign in standard administrative systems.
How is Megalencephaly-Capillary Malformation-Polymicrogyria Syndrome diagnosed?
Diagnosis of Megalencephaly-Capillary Malformation-Polymicrogyria Syndrome is primarily clinical, based on the presence of megalencephaly (enlarged brain), cutaneous capillary malformations, and cortical malformations like polymicrogyria. Genetic testing is essential to confirm the diagnosis, which is typically caused by somatic mosaic mutations in the PIK3CA gene. Currently, 23 members of the DiseaseMaps.org community are living with this diagnosis, sharing their unique clinical journeys.
What are the clinical features of MCAP?
MCAP is a multisystem condition that requires a multidisciplinary approach. Common features include:
- Neurological: Megalencephaly, polymicrogyria, and developmental delays.
- Vascular: Capillary malformations, often appearing as a pinkish-red rash on the face or body.
- Growth: Overgrowth of limbs, digits (macrodactyly), or hemihypertrophy.
- Other: Increased risk for seizures and systemic vascular issues.
Next steps
- Consult a geneticist to discuss PIK3CA testing and clinical management.
- Coordinate care with a pediatric neurologist and a vascular specialist.
- Connect with the 23 members of the DiseaseMaps.org community to share experiences and supportive resources.
- Request that your care team utilize the most descriptive available codes (Q04.8) to ensure accurate medical record keeping.
Medical disclaimer: This information is for educational purposes only and does not constitute medical advice; please consult with your healthcare provider for clinical decisions.
References
- Orphanet: Megalencephaly-capillary malformation-polymicrogyria syndrome (ORPHA:209939).
- NIH Genetic and Rare Diseases (GARD) Information Center: MCAP syndrome.
- OMIM (Online Mendelian Inheritance in Man): #603387 (Megalencephaly-Capillary Malformation Syndrome).
- National Library of Medicine (PubMed): Literature review on PIK3CA-related overgrowth spectrum (PROS).
