Introduction: Cerebral palsy (CP) represents a group of chronic and non-progressive disorders secondary to brain dysgenesis or injury. It is characterized by significant impairment in movement and posture that begins during infancy or early childhood. Dyskinetic CP is characterized by abnormal movements, with fluctuating patterns of tone and posture. Because the diagnosis of cerebral palsy is performed through clinical aspects, primary dystonia due to genetic cause is often misdiagnosed as dyskinetic cerebral palsy. We report a case with primary dystonia due to GNAO1 gene mutation who was diagnosed dyskinetic cerebral palsy previously.
Case: A 7-month-old girl was referred to the outpatient rehabilitation clinic because of delayed development. The patient had been born at 38 weeks of gestation by vaginal delivery. The prenatal and perinatal course was non-specific. There was no family history of delayed development or other known hereditary diseases. The patient had one older sibling, who has no developmental abnormality. The birth weight was 2800g (16th Percentile). On the examination, there was increased muscle tone and primitive reflexes, with grossly hypertonic posture, extension tendency of all extremities, and extensor thrust. Head control was poor. She showed excessive involuntary movements on bilateral upper and lower limbs. The electrodiagnosic study, brain MRI and neonate screening test for metabolic disorders were normal. Chromosomal abnormality was not seen. At that time, she was diagnosed dyskinetic cerebral palsy. At 36-month-old, Bayley Scales of Infant and Toddler Development showed below 0.1 percentile of development in all domains (cognitive development 3 month 20 days, receptive communication 4 month 10 days, expressive communication 2 month 20 days, fine motor development 3 month 10 days, and gross motor development 1 month of age). At 4-year-old, follow-up brain MRI was showed no abnormality. She was referred to the genetic clinic to assess hereditary dystonia. The multi-gene panel study related with primary dystonia which was developed by us was performed (Table 1). We found a heterozygous variation in the patient’s GNAO1: c.607G>A (p.Gly203Arg), which is related with a neurodevelopmental disorder with involuntary movements.
Clinicians should be cautious that patients diagnosed with cerebral palsy in full-term births without specific MRI findings may have genetic diseases masquerading as cerebral palsy.
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