Genetic counseling: Cerebral Palsy

Cerebral palsy

Contracting

 * What is your understanding of why you were referred to genetics?
 * What questions or concerns would you like us to address today?
 * Set agenda for the session

Etiology

 * Heterogeneous group of conditions usually leading to ataxia
 * Sometimes inherited in autosomal dominant, autosomal recessive, or X-linked form in familial cerebellar hypoplasia


 * Congenital and childhood-onset ataxias tend to be autosomal recessive
 * Adult-onset conditions tend to be autosomal dominant
 * May also be due to teratogenic insults
 * Methymercury
 * Retinoic acid
 * Anticonvulsants
 * Most common cause is hypoxic/ischemic injury in perinatal period or early childhood
 * Anoxia
 * Trauma to the brain at birth
 * Can be caused by cerebral injury later in life

Clinical Features

 * Several classes with different features
 * Spastic diplegia
 * Onset several weeks or months after birth
 * Delay in normal development, especially motor skills
 * Results from prenatal or perinatal insult
 * Walking attempted much later and results in characteristic stance and gait
 * Legs advanced stiffly in short steps like arc of circle
 * May have scissors gait with crossing over of legs
 * Lower legs splayed out, feet flexed and turned in, heels not touching ground
 * Posture alternates between extremes of supination and pronation
 * Walking accompanied often by rotary movements of neck and facial grimacing
 * Legs short and small but muscles not atrophic
 * Arms may also be mildly affected
 * Hemiplegia
 * Difference in function of right and left extremities noticed after birth or 6-12 months
 * Accounts for about 1/3 of children with cerebral palsy
 * Affects arms first, noticed in legs when learning to walk
 * Mental defects depend on whether brain lesion confined to one hemisphere
 * Convulsions (35-50%)
 * Seizures may accompany onset if develops during childhood
 * Usually limited to hemiplegic side of body
 * May persist throughout life
 * Double hemiplegia
 * Occurs less frequently than hemiplegia
 * Bilateral weakness of face, arms, and legs
 * Begins at any age due to acquired cerebral disease
 * May be due to bilateral cerebral lesion or high cervical cord lesion
 * May also be produced in infant by fracture-dislocation of cervical spine by breech delivery
 * Arms severely affected
 * Congenital choreoathetosis
 * Recognized after several months or a year
 * Causes some combination of chorea, athetosis, ballismus, myoclonus, and dystonia
 * Causes defect in voluntary movement
 * May be mild resulting in "fidgets"
 * May be severe, intense involuntary movements
 * Even with rehabilitation, the most severe rarely achieve enough motor control to live independent life
 * Intelligence may not be affected
 * Kernicterus
 * Was common when postnatal serum bilirubin was kept below 15 mg/dL
 * Majority of infants die within 1 or 2 years
 * Survivors usually mentally retarded, deaf, and totally unable to sit, stand, or walk
 * Several patients reportedly were not mentally retarded and learned to walk backwards
 * Have rigid limbs

Management/Treatment Options

 * Outcome depends on severity of associated intellectual handicaps
 * Early application of stretching to prevent contractures
 * Orthopedic appliances and surgical procedures to improve mobility
 * Special education to help with motor problems and intellectual involvement
 * Prevention is great challenge
 * Prevention of kernicterus by phototherapy has helped
 * Providing low-birth weight infants with extra care may help
 * More prone to respiratory distress
 * Must provide good surveillance of respiratory function

Differential Diagnosis

 * Leukodystrophy - spinal tap showing elevated spinal fluid indicates leukodystrophy
 * Hydrocephaly if child has large head
 * Tumor of cerebral hemishphere - disease is progressive
 * Spinal cord lesions - weakness limited to lower extremities
 * Muscular dystrophy - tendon reflexes would be normal
 * Ataxia telangiectasia

Recurrence Risks

 * Depends if cause of cerebral palsy can be determined
 * Autosomal recessive
 * Each pregnancy from heterozygote parents has 25% risk of child being affected
 * Each pregnancy has 50% risk of being carrier
 * Autosomal dominant
 * Each child born to affected parent has 50% chance of being affected
 * May also occur due to new mutation so low recurrence risk
 * X-linked
 * Sons of affected males not affected
 * Daughters of affected males must be affected
 * Daughters of carrier females 50% risk of being carriers
 * Sons of carrier females 50% risk of being affected
 * Most cases probably caused by hypoxic or ischemic injury to brain so recurrence risk is low

Psychosocial Issues

 * Parental guilt
 * Burden of disease that requires daily management
 * Social stigma
 * Financial pressures, disruption of daily activities for special therapies, orthotics, or other needs
 * Potential need for lifetime care