Pontine myelinolysis in a child with carbamate poisoning.

Carbamate and organophosphate pesticides are widely used all over the world. Poisoning with these substances may produce both immediate and delayed neurotoxic effects. We report the case of a 4-year-old boy who was admitted to the Pediatric Department of the Second University of Naples for evaluation of stupor, lethargy, severe hypotonia, generalized weakness of his arms and legs, ataxia, dysmetria, miosis, excessive salivation and tearing. The pesticide carbaryl (1-naphthyl-N-methylcarbamate) was identified in blood and urine samples. On admission, magnetic resonance imaging (MRI) was unremarkable; on day 11, MRI showed central pontine myelinolysis. The demyelination improved after 4 months and disappeared after 2 years. Various underlying and concomitant diseases have been described in children with central pontine myelinolysis but, to our knowledge, the finding of pontine myelinolysis after carbamate poisoning has not yet been described.

Genetic heterogeneity of FG syndrome: a fourth locus (FGS4) maps to Xp11.4-p11.3 in an Italian family.

FG syndrome (FGS, MIM 305450) is a rare X-linked recessive disorder comprising mental retardation and multiple malformations. Various families have been described to date, increasing our knowledge of the phenotype variability and making the clinical diagnosis complex, especially in sporadic patients. The first locus for FG syndrome (FGS1) was linked to chromosome region Xq12-q21.31, but other families have been excluded from this locus. The genetic heterogeneity of FG syndrome has been confirmed by analysis of an X chromosome inversion [inv(X)(q11q28)] in an affected boy and in his mentally retarded maternal uncle, suggesting that an additional locus for FG syndrome (FGS2, MIM 300321) is located at either Xq11 or Xq28. Recently, a third locus (FGS3) has been mapped to Xp22.3. We have identified and clinically characterized an Italian FG family, including 31 members with three affected males in two generations and two obligate carriers. We have excluded linkage to known FGS loci, whereas an extensive study of the whole X chromosome has yielded a maximum LOD score (Z(max)) of 2.66 (recombination fraction=0) for markers between DXS8113 and sWXD805. This new locus for FG syndrome corresponds to a region of approximately 4.6 Mb on the X chromosome.