LISSENCEPHALY

ALTERNATE NAMES

Lissencephaly Type I; LIS1; Classical Lissencephaly; X-Linked Lissencephaly; XLIS; Lissencephaly with Agenesis of the Corpus Callosum; Lissencephaly with Cerebellar Hypoplasia; Microlissencephaly; Miller-Dieker Syndrome

DESCRIPTION

Lissencephaly is a brain malformation in which the physical structure of the brain did not develop correctly during fetal development. Lissencephaly is characterized by the absence of normal folds and ridges (convolutions) in the cerebral cortex, resulting in a nearly smooth brain and an abnormally small head (microcephaly). The cerebral cortex of the brain is involved in several functions of the body including determining intelligence, personality, motor function, planning and organization, and touch sensation.

Children with this condition appear normal at birth, but hypotonia (loss of muscle tone) and trouble with feeding soon becomes apparent as does poor head growth. Children with this disorder can also have varying degrees of intellectual disability, seizures, difficulty swallowing and eating, difficulty controlling muscles (ataxia), stiffness or spasticity of arms and legs, and slowed growth and developmental delays.

DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING

The diagnosis of lissencephaly is usually made by computed tomography (CT), or MRI. Physical findings are variable, including hypo- or hypertonia.

ICD-9: 742.2

ONSET AND PROGRESSION

The prognosis for children with lissencephaly is poor with many dying in infancy, and the remainder showing no significant development beyond a 3 -5 month level.

TREATMENT

There is no way to reverse the effects of lissencephaly. Supportive management of lissencephaly includes treatment of seizures, and physical and occupational therapies to lessen spasticity. Feeding difficulties are treated with a gastrostomy tube. Respiratory problems are the most common causes of death.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for evaluation:

• Clinical history and examination that describes the diagnostic features of the impairment

• Cranial MRI or CT scans

• Developmental assessment or psychological testing to address allegations of mental impairment may be warranted.

Suggested Listings for Evaluation:

DETERMINATION

LISTING

Meets Listing

110.08

111.02

112.02

Medical Equals