Short answer · Medically reviewed summary · Last updated: 2026-05-08
Lissencephaly is classified under ICD-10 code Q04.3 (Other specified congenital malformations of brain) and ICD-9 code 742.2 (Reduction deformities of brain). These diagnostic codes are essential for medical billing, clinical documentation, and accessing specialized services for those living with this rare brain malformation. What is the clinical significance of Lissencephaly? Lissencephaly, often referred to as "smooth brain," is a rare, gene-linked brain malformation characterized by the absence of normal convolutions (folds) in the cerebral cortex.
ICD10 code of Lissencephaly and ICD9 code
ICD-10 and ICD-9 codes for Lissencephaly, with classification details for clinicians, coders and patients.
Lissencephaly is classified under ICD-10 code Q04.3 (Other specified congenital malformations of brain) and ICD-9 code 742.2 (Reduction deformities of brain). These diagnostic codes are essential for medical billing, clinical documentation, and accessing specialized services for those living with this rare brain malformation.
What is the clinical significance of Lissencephaly?
Lissencephaly, often referred to as "smooth brain," is a rare, gene-linked brain malformation characterized by the absence of normal convolutions (folds) in the cerebral cortex. The condition results from defective neuronal migration during fetal development. Because Lissencephaly is a spectrum disorder, the severity of developmental delays, seizures, and motor impairment varies significantly among the 11 individuals currently sharing their experiences on DiseaseMaps.org.
How is Lissencephaly diagnosed and classified?
Diagnosis typically involves neuroimaging, such as MRI, to visualize the characteristic smooth surface of the brain. Clinicians use specific criteria to distinguish between various forms of Lissencephaly, which are often categorized by the specific gene mutation involved, such as PAFAH1B1 (formerly LIS1) or DCX. Genetic testing is a critical component of the diagnostic process to determine the underlying cause and potential recurrence risk for families.
What are the common features associated with Lissencephaly?
While every child's journey is unique, individuals diagnosed with Lissencephaly often face a range of neurological challenges. Common clinical features include:
- Severe developmental delay and intellectual disability.
- Infantile spasms or other forms of treatment-resistant epilepsy.
- Microcephaly (an unusually small head size).
- Feeding difficulties and failure to thrive due to swallowing dysfunction.
- Muscle spasticity or hypotonia (low muscle tone).
Next steps
- Consult with a pediatric neurologist or a clinical geneticist to discuss genetic testing options and prognosis.
- Connect with the 11 members of the DiseaseMaps.org community to share experiences and supportive resources.
- Work with a multidisciplinary team including physical, occupational, and speech therapists to maximize developmental potential.
- Reach out to organizations like the NIH Genetic and Rare Diseases Information Center (GARD) for verified clinical updates.
Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment; always seek the guidance of your physician regarding a medical condition.
References
- NIH Genetic and Rare Diseases Information Center (GARD): Lissencephaly entry.
- Orphanet: Rare disease database for Lissencephaly (ORPHA:536).
- OMIM (Online Mendelian Inheritance in Man): Clinical synopsis of Lissencephaly.
- The Lissencephaly Network: Patient-centered support and resource hub.
