Dominantly inherited distal nemaline/cap myopathy caused by a large deletion in the nebulin gene.

We report the first family with a dominantly inherited mutation of the nebulin gene (NEB). This ∼100 kb in-frame deletion encompasses NEB exons 14-89, causing distal nemaline/cap myopathy in a three-generation family. It is the largest deletion characterized in NEB hitherto. The mutated allele was shown to be expressed at the mRNA level and furthermore, for the first time, a deletion was shown to cause the production of a smaller mutant nebulin protein. Thus, we suggest that this novel mutant nebulin protein has a dominant-negative effect, explaining the first documented dominant inheritance of nebulin-caused myopathy. The index patient, a young man, was more severely affected than his mother and grandmother. His first symptom was foot drop at the age of three, followed by distal muscle atrophy, slight hypomimia, high-arched palate, and weakness of the neck and elbow flexors, hands, tibialis anterior and toe extensors. Muscle biopsies showed myopathic features with type 1 fibre predominance in the index patient and nemaline bodies and cap-like structures in biopsies from his mother and grandmother. The muscle biopsy findings constitute a further example of nemaline bodies and cap-like structures being part of the same spectrum of pathological changes.

Primary intraocular lymphoma: improving the diagnostic procedure.

OBJECTIVE: To analyze the clinical features of primary intraocular lymphoma (PIOL) and to describe cytochemical and immunocytochemical findings of the vitreous specimens as well as the reasons for delayed diagnosis of PIOL. DESIGN: Prospective noncomparative study. PARTICIPANTS: Eleven patients referred to the uveitis or medical retina units, Department of Ophthalmology, University of Helsinki, were diagnosed as having PIOL between 2000 and 2005. The median follow-up of the patients was 32 months. METHODS: Clinical features and diagnostic workup of uveitis were described. Twelve vitrectomies were performed on 9 patients. The first 5 biopsies were fixed in an equal volume of 50% alcohol. The specimens of the next 7 vitrectomies were handled without alcohol, and tissue culture medium was added to the samples. MAIN OUTCOME MEASURES: Clinical features of PIOL, intervals from ocular symptoms and from first ophthalmological examination to diagnosis, and the role of a proper handling of the vitreous sample in the diagnosis of PIOL. RESULTS: Six females (54%) and 5 males (46%) (median age, 61 years) were included. Ten patients had ocular symptoms for 1 to 30 months (median, 8) before the first contact with an ophthalmologist. Uveitis was bilateral in 9 patients. Vitreitis was seen in all patients, and it was severe in 8. Fundus lesions dominated in 3 patients. Six patients lost useful vision in one eye before the diagnosis of PIOL. Cytologic and immunohistochemical stainings prepared of the unfixed vitreous specimens showed PIOL in 6 patients. The samples fixed in alcohol were nondiagnostic in 4 patients, and in them, verification of diagnosis was based on brain biopsy (3) or cerebrospinal fluid (1) findings. Seven patients died due to primary nervous system lymphoma. CONCLUSIONS: Diagnosis of PIOL is difficult but can be improved. Severe bilateral vitreitis in an elderly patient is a characteristic finding of PIOL. Alcohol fixation may jeopardize the identification of PIOL cells in the vitreous sample. Optimal handling of the vitreous specimens and examination of the slides by an experienced cytopathologist are critical in the diagnostic workup of PIOL.