Glutaric aciduria type 1: an underdiagnosed cause of encephalopathy and dystonia-dyskinesia syndrome in children

Clinical Characteristics Suggestive of a Genetic Cause in Cerebral Palsy: A Systematic Review

BACKGROUND

Cerebral palsy (CP) is a clinical diagnosis and was long categorized as an acquired disorder, but more and more genetic etiologies are being identified. This review aims to identify the clinical characteristics that are associated with genetic CP to aid clinicians in selecting candidates for genetic testing.

METHODS

The PubMed database was systematically searched to identify genes associated with CP. The clinical characteristics accompanying these genetic forms of CP were compared with published data of large CP populations resulting in the identification of potential indicators of genetic CP.

RESULLTS

Of 1930 articles retrieved, 134 were included. In these, 55 CP genes (described in two or more cases, n = 272) and 79 candidate genes (described in only one case) were reported. The most frequently CP-associated genes were PLP1 (21 cases), ARG1 (17 cases), and CTNNB1 (13 cases). Dyskinesia and the absence of spasticity were identified as strong potential indicators of genetic CP. Presence of intellectual disability, no preterm birth, and no unilateral distribution of symptoms were classified as moderate genetic indicators.

CONCLUSIONS

Genetic causes of CP are increasingly identified. The clinical characteristics associated with genetic CP can aid clinicians regarding to which individual with CP to offer genetic testing. The identified potential genetic indicators need to be validated in large CP cohorts but can provide the first step toward a diagnostic algorithm for genetic CP.

Evaluation of a child with cerebral palsy

Evaluation of a child with cerebral palsy (CP) requires a multidisciplinary approach with a team of professionals comprising of a pediatrician or pediatric neurologist, occupational therapist, a physiotherapist, child psychologist, and a social worker. The assessment is necessary to confirm the diagnosis, determine the cause, assess the motor function and associated problems. The diagnosis of CP is clinical but selected investigations may be required for ascertaining the cause. Evaluation includes assessment for common medical problems of childhood particularly nutritional disorders and assessment of family functioning. Additional disabilities are common. Routine assessment of vision and hearing is required in children with CP. Since CP is a changing disorder, some limitations may not be evident early in life but manifest in the school age or later. The evaluation of a child with CP is an ongoing process and should be a part of continuing care as the child grows from infancy to adolescence.

Evaluation of the child with cerebral palsy

Cerebral palsy (CP) is a common problem, occurring in about 2 to 2.5 per 1000 live births. The diagnosis of CP is based upon a history of abnormal motor development that is not progressive coupled with an examination (e.g. hypertonicity, increased reflexes, clonus) "placing" the lesion in the brain. In order to establish that a brain abnormality exists in children with CP that may, in turn, suggest an etiology and prognosis, neuroimaging is recommended with magnetic resonance imaging preferred to computed tomography. Metabolic and genetic studies should be obtained if there are atypical features in the history or on the examination. Detection of a brain malformation in a child with CP might suggest an underlying genetic or metabolic etiology. As cerebral infarction is high in children with hemiplegic CP, diagnostic testing for coagulation disorders should be considered. However, there is insufficient evidence at present to be precise as to what studies should be ordered. An electroencephalogram is not recommended unless there are features suggestive of epilepsy or a specific epileptic syndrome. As children with CP may have associated deficits of mental retardation, ophthalmologic and hearing impairments, speech and language disorders and oral-motor dysfunction, screening for these conditions should be part of the initial assessment.

Dystonia in a patient with ring chromosome 21

Dystonia associated with chromosomal abnormalities is typically attributed to chromosomal deletions. We describe a patient with ring chromosome 21, with karyotype 46XX,r(21)(p11.2q22.3); 46,XX,dic r(21)(p11.2q22.3); 45, XX, -21, who developed childhood onset cervical dystonia.

Hereditary causes of chorea in childhood

Chorea and athetosis are rare presenting symptoms in childhood. Chorea can be a presenting symptom in a number of hereditary diseases, including neurodegenerative diseases, paroxysmal diseases, and metabolic diseases. In these situations, family history, associated symptoms, and other physical findings will often enable a correct diagnosis. Benign childhood chorea is probably a genetically heterogeneous group of disorders, generally without other symptoms. Clinical aspects of these disorders are reviewed here.

Age at symptom onset predicts severity of motor impairment and clinical outcome of glutaric acidemia type 1

OBJECTIVES

In patients with glutaric acidemia type 1 (GAI), biochemical and molecular markers fail to predict the course of individual patients; therefore we sought to identify nonbiochemical variables that correlate with severity of motor deficits or overall clinical outcome.

STUDY DESIGN

Archival data was collected from 42 published articles describing 115 patients with GA1. A forward, stepwise, multiple regression analysis was used to find predictors for outcome.

RESULTS

Analyses show that in patients who did not have a precipitating illness before the first appearance of motor symptoms, the age at onset was significantly associated with the severity of motor impairments and overall clinical outcome. In patients who had a precipitating illness, the age at onset did not predict the outcome. In both groups of patients, basal ganglia degeneration, enlargement of spaces containing cerebrospinal fluid, and white matter abnormalities were indicative of a poorer prognosis. Treatment given after the appearance of symptoms was not associated with a better clinical outcome or fewer motor deficits.

CONCLUSION

Because the age at symptom onset can significantly predict the severity of motor deficits and the overall outcome, it is important to identify patients with GA1 as early as possible. Several studies suggest that presymptomatic treatment may prevent or postpone the onset of symptoms.