Handbook of Genetic Counseling/Cerebral Palsy

Cerebral palsy

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Etiology

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

Inheritance	Condition	Features
Autosomal Dominant	Cerebellar Vermis Aplasia	Female Sex Bias
Autosomal recessive	Cerebellar hypoplasia with or without retinal pigment abnormality	Presents in infancy
	Cerebellar granule cell hypoplasia	2 or more types, one with severe microcephaly
	Cerebellar ataxia with neuronal migration defect	Absence of muscle disease
	Pontoneocerebellar atrophy with extrapyramidal dyskinesia
	Fatal infantile olivopontocerebellar hypoplasia	Neronal loss in olives and pontine nuclei, white matter gliosis, microcephaly
	Cerebellar atrophy with infantile striatal degeneration	Progressive epilepsy, mental handicap, death after febrile illness
	Gillespie syndrome	Cerebellar atrophy, aniridia, mental handicap
	Cerebellar atrophy and anterior horn cell disease	Neuromuscular condition similar to type I SMA
	Cerebellar hypoplasia with progressive pancytopenia (Hyoyeraal-Hreidarsson)	Males with growth retardation, microcephaly, pancytopaenia (X-linked?)
	Cerebellar atrophy, renal and liver disease	Carbohydrate-deficient glycoprotein syndrome
X-linked (possibly)	Paine syndrome	Hypoplasia of pons and olives, microcephaly, epilepsy, mental handicap, spasticity
	X-linked dominant vermis aplasia	Preponderance of female-to-female transmission
	Cerebellar vermis aplasia, holoprosencephaly syndrome	Male sibs affected by holoprosencephaly and/or vermis aplasia

- 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

References

"Abnormalities of Motor Function (Cerebral Palsy)." Principles of Internal Medicine (1994): 2342.
"Cerebellar Hypoplasias." Principles and Practice of Medical Genetics (1997): 2154-2156.
"Cerebral Palsy (Little Disease)." Textbook of Pediatrics (1979): 1759-1761.

Notes

The information in this outline was last updated in 2002.

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