Predominant dystonia with marked cerebellar atrophy: a rare phenotype in familial dystonia.

BACKGROUND: Dystonia syndromes constitute a heterogeneous group of phenotypes that may be caused by different heredodegenerative, metabolic, or genetic diseases. OBJECTIVE: To describe the characteristics of an unusual dystonia-plus phenotype associated with cerebellar atrophy. METHODS: We selected patients with predominant dystonia and cerebellar atrophy among the 861 families referred to us for genetic testing from 1992 to 2003. The main secondary heredodegenerative causes and the major genes responsible for hereditary dystonias and autosomal dominant or recessive ataxias were excluded. RESULTS: We identified 12 patients in 8 families with an unusual dystonia-plus phenotype characterized by dystonia and cerebellar atrophy on brain MRI. The mean age at onset was 27.3 +/- 11.5 years (range: 9 to 42 years) and the mean disease duration 14.7 +/- 7.7 years (range: 4 to 30). At onset, dystonia was focal or multifocal, mainly affecting vocal cords (n = 8) and upper limbs (n = 2). During the disease course spasmodic dysphonia became severe in five patients, leading to complete aphonia in two. Dystonia became generalized in five. Cerebellar ataxia was limited to unsteadiness in most patients and progressed very slowly. The paucity of clinical cerebellar signs contrasted with the marked cerebellar atrophy on brain MRI in most patients. Four families with two affected sibs support the hypothesis of an autosomal recessive disorder. However, X-linked inheritance is possible since only men were affected. CONCLUSION: We have characterized an unusual familial phenotype associating dystonia and cerebellar atrophy in 12 male patients.

Modulated photoacoustic spectroscopy study of an artificial tanning on human skin induced by dihydroxyacetone.

A modulated photoacoustic spectroscopy study on the effect of dihydroxyacetone, commonly used for artificial tan, is presented. The study was carried out in the presence and absence of dimethylisosorbide (a solvent for dihydroxyacetone) on fresh human skin, obtained from the breast region of recent autopsy cases (two females), at a frequency of 25 Hz, which enabled us to study the effect at a depth of 30 microm in the stratum corneum and beneath. By monitoring the photoacoustic signal intensity with time in the region of 300-400 nm, which is a specific region for melanin pigment, it is demonstrated that dihydroxyacetone in combination with dimethylisosorbide enhances the process of tanning. Dihydroxyacetone also has an effect on the amino acids and nucleic acids which is bad for the skin.

Study of the diffusion of some emulsions in the human skin by pulsed photoacoustic spectroscopy.

We previously used pulsed photoacoustic spectroscopy (PPAS) to quantify sunscreen diffusion into human skin, and suggested a methodology to evaluate the time and the depth diffusion profile. These results were obtained by the analysis of the photoacoustic maximum response signal Pmax decrease, the time delay tmax and the Fourier transform representation of the photoacoustic signal. In this study we present the results obtained for diffusion of four typical emulsions used in sunscreen compositions that show, for the first time, a particular behaviour for one of these emulsions due to a chemical reaction inside the skin during the diffusion process. This result provides a particularly interesting technique through the PPAS, to evaluate in situ the eventual chemical reactions that can occur during drug diffusion into human skin.