Ethylmalonic encephalopathy
Incidence
Autosomal recessive inheritance apparently.
Clinical Characteristics
Ethylmalonic encephalopathy, first described by Burlina et al. (1991), is a syndrome characterized by ethylmalonic and methylsuccinic aciduria and lactic acidemia associated with developmental delay, acrocyanosis, petechiae, and chronic diarrhea. The underlying metabolic defect is unknown. The in vitro activities of short chain acyl-CoA dehydrogenase (SCAD) and 2-methyl-branched chain acyl-CoA dehydrogenase, 2 enzymes whose deficiencies could theoretically produce the biochemical findings observed in ethylmalonic encephalopathy, were found to be normal (Burlina et al., 1994). Nowaczyk et al. (1998) reported the cases of 2 sibs with ethylmalonic encephalopathy and central nervous system malformations. The girl had primary tethered cord. Her younger brother, who was evaluated at the age of 4 years because of a similar phenotype (episodic ataxia, chronic diarrhea, and acrocyanosis), had cerebellar tonsillar ectopia (Chiari I malformation). These anomalies were demonstrated by magnetic resonance imaging (MRI). The following features are found very frequently: acrocyanosis, bruisability, paraparesis/quadraparesis, hypertonia/spasticity/rigidity, malabsorption/chronic diarrhoea, neurological structural anomalies, mental retardation (moderate/severe).
Precipitants
None.
Provocation Tests
None.
Diagnostic Procedures
It is a clinical diagnosis, associated with lab abnormalities: ethylmalonic and methylsuccinic aciduria and lactic acidemia