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.

Unbalanced X-chromosome inactivation with a novel FVIII gene mutation resulting in severe hemophilia A in a female.

This report is of a 14-month-old girl affected with severe hemophilia A. Both her parents had normal values for factor VIII activity, and von Willebrand disease type 2N was excluded. Karyotype analysis demonstrated no obvious alteration, and BclI Southern blot did not reveal F8 gene inversions. Direct sequencing of F8 gene exons revealed a frameshift-stop mutation (Q565delC/ter566) in the heterozygous state in the proposita only. F8 gene polymorphism analysis indicated that the mutation must have occurred de novo in the paternal germline. Furthermore, analysis of the pattern of X chromosome methylation at the human androgen receptor gene locus demonstrated a skewed inactivation of the derived maternal X chromosome from the lymphocytes of the proband's DNA. Thus, the severe hemophilia A in the proposita results from a de novo F8 gene frameshift-stop mutation on the paternally derived X chromosome, associated with a nonrandom pattern of inactivation of the maternally derived X chromosome. (Blood. 2000;96:4373-4375)

A novel variant of transthyretin (Glu42Asp) associated with sporadic late-onset cardiac amyloidosis.

A sixty-three year old French man presented with isolated late-onset amyloid cardiomyopathy proven by endomyocardial biopsy. There was no known family history of amyloidosis. Immunohistochemistry of cardiac deposits suggested that amyloi fibrils were derived from transthyretin. DNA sequencing revealed a point mutation in exon 2 of the transthyretin gene responsible for a novel amyloidogenic variant Asp42.

Prevalence, male germ-line origin and new patterns of inversions in haemophilia A.

Following the discovery of the FVIII gene inversion by Lakich et al. [1] and Naylor et al. [2], we have investigated this mutation in 108 French and Algerian severe haemophilia A patients. We have found that only 29 severe haemophiliacs (27%) exhibited the rearrangement whereas Lakich et al. [1] and Naylor et al. [2] respectively estimated the inversion frequency at 47% and 42% in severe haemophiliacs. The reason for this discrepancy is not accounted for. In this study, we observed two novel patterns of inversions as yet unreported. We did not find any correlation between the presence of the inversion and a particular RLFP haplotype, or ethnic origin, or the absence of a FVIII inhibitor. Among the cases with the inversion, the proportion of sporadic and transmitted cases was roughly equivalent and we also confirm that the inversion occurs preferentially in the male germ-line.

Late-onset familial amyloid polyneuropathy with the TTR Met 30 mutation in France.

Four unrelated French cases of familial amyloid polyneuropathy are reported. Clinical onset ranged from the sixth to the ninth decade. Sensory signs were predominant initially in the lower limbs; motor changes, and in one case autonomic involvement, appeared later. Amyloid disease was clinically limited to the peripheral nervous system. In two cases, there was no evidence of familial disease. DNA analysis was performed in these four patients and in two children of Patient 1. Restriction analysis of amplification products of exon 2 of the transthyretin gene was positive for the valine 30 to methionine mutation. These four unrelated patients live in different areas of France. Further studies are needed to determine whether these mutations have a common origin and whether they are related to the Portuguese mutation.