Low-Colony Counts of Nontuberculous Mycobacteria: Clinical Significance Analysis / 대한임상미생물학회지

BACKGROUND: Diagnosis of nontuberculous mycobacterium (NTM) is challenging, and clinical, radiological and microbiological criteria should be met. Traditionally, culture results on solid media have been reported semi-quantitatively, but no study exists regarding the clinical significance of low-colony count culture reports. The authors of the present study analyzed the clinical significance of low-colony count specimens of NTM with a greater than three-year follow-up period. METHODS: A total of 341 clinical isolates were evaluated among the isolates at Seoul National University Hospital and Seoul National University Borame Hospital from October 2005 to September 2006. Colony count less than 50 was considered a low-colony count specimen. Identifications of NTM from all the isolates were performed using a DNA chip (PCR reverse hybridization, LG Life Science, Korea). Clinical significance was analyzed by reviewing the medical records of patients with greater than three years of follow-up data after NTM isolation from respiratory samples. RESULTS: NTM lung disease was observed in 27.0% of the patients with low-colony count specimens among 167 patients with respiratory samples, and 70.4% of the patients were treated. The low-colony count patients had less NTM lung disease, longer incubation period, and less acid fast bacilli-positivity than patients with a colony count greater than 50. CONCLUSION: The prevalence of NTM lung disease with a low-colony count specimen was greater than 25%. In a clinical setting, NTM lung disease should not be excluded only on the basis of a low-colony count.

A Novel-Thalassemic Mutation, Codons 89/90-TG, Found in Two Korean Families / 대한임상병리학회지

We describe a novel-thalassemia mutation, the deletion of TG at codons 89/90 of the globin gene, found in two unrelated Korean families. Their hematological findings varied, but some patients showed prominent anemia. This mutation would introduce a premature stop codon (TGA) at codon 93. But a RNA study revealed that the / ratio was within normal range, and the amount of the mutant -globin RNA was comparable to that of normal-globin RNA. These data suggests this novel mutation as a dominant type. The haplotype and frameworks linked to the mutation were different between the two families.

Spinocerebellar ataxia type 2 in seven Korean families: CAG trinucleotide expansion and clinical characteristics

Studies on spinocerebellar ataxias (SCA) have been hampered by a lack of disease markers. Clinical and pathological heterogeneity also made the classification unreliable. Linkage studies established that there are multiple subtypes of SCA. Five types are found to have unstable CAG expansion; the diagnosis can be established by molecular genetic study. Therefore, we systemically screened degenerative ataxia patients for these five SCA types, and identified eight patients with SCA2 (seven from six families and one sporadic case). This paper presents the clinical information on the seven patients, whose clinical information was available in detail. CAG repeat expansion in the patients ranged from 38 to 47 (normal control, 19 to 27). The onset ages ranged from 16 to 41 with 27.1 years as the mean, which correlated inversely with repeat lengths. All patients presented dysarthria and gait ataxia. Upper limb dysmetria or dysdiadochokinesia appeared later but progressed, causing severe disability. Slow saccade (4 patients in 7) and decreased DTR (4 in 7) were common. MRIs showed severe atrophy of the brainstem and cerebellum in all patients. We conclude that SCA2 is the most frequent type in Korea and carries rather pure cerebellar syndrome, slow saccade, and hyporeflexia.

Clinical analysis of huntington's disease in Korea

Huntington's disease(HD) is clinically diagnosed by the triad of autosomal dominant inheritance, involuntary movements mainly chorea, and dementia. The phenotype of HD is variable and other diseases can have the same phenocopy. A definite diagnosis of Huntington's disease cannot be made by clinical informations alone Pathologic or genetic studies was necessary to exclude other neurodegenerative diseases which may present with familial dementia or chorea. Therefore, genetic studies of HD become essential for confirmatory diagnosis. Recent discovery of an expanded CAG trinucleotide repeat at the telomeric position of chromosome 4p made the diagnosis possible even in sporadic and presymptomatic cases. We previously demonstrated expantion of CAG repeats in clinically diagnosed HD, and were able to find presymptomatic. We herein present the clinical and genetic information in all the cases of genetically confirmed HD. 1) There was a clear gap between the number of CAG repeats in HD and normal and disease control. 2) Two out of three patients who had chorea without family history were confirmed as HD by genetic study. 3) One who had psychosis and a family history of HD was shown not to be HD. 4) We found 12 asymptomatic cases with HD mutation during family screening. 5) Caudate atrophy in MRI was not seen in the early stage of HD. Our data confirms that gene analysis is a powerful tool to make a diagnosis of HD even in sporadic and presymptomatic cases. Proper genetic counselling after judicious preparation of the family and society is sorely needed.

Clinical analysis of huntington's disease in Korea

Huntington's disease(HD) is clinically diagnosed by the triad of autosomal dominant inheritance, involuntary movements mainly chorea, and dementia. The phenotype of HD is variable and other diseases can have the same phenocopy. A definite diagnosis of Huntington's disease cannot be made by clinical informations alone Pathologic or genetic studies was necessary to exclude other neurodegenerative diseases which may present with familial dementia or chorea. Therefore, genetic studies of HD become essential for confirmatory diagnosis. Recent discovery of an expanded CAG trinucleotide repeat at the telomeric position of chromosome 4p made the diagnosis possible even in sporadic and presymptomatic cases. We previously demonstrated expantion of CAG repeats in clinically diagnosed HD, and were able to find presymptomatic. We herein present the clinical and genetic information in all the cases of genetically confirmed HD. 1) There was a clear gap between the number of CAG repeats in HD and normal and disease control. 2) Two out of three patients who had chorea without family history were confirmed as HD by genetic study. 3) One who had psychosis and a family history of HD was shown not to be HD. 4) We found 12 asymptomatic cases with HD mutation during family screening. 5) Caudate atrophy in MRI was not seen in the early stage of HD. Our data confirms that gene analysis is a powerful tool to make a diagnosis of HD even in sporadic and presymptomatic cases. Proper genetic counselling after judicious preparation of the family and society is sorely needed.

Gene Analysis in Huntington Disease

BACKGROUND & OBJECTIVE: Huntington disease(HD) is clinically diagnosed by the triad of autosomal dominant inheritance, involuntary movements mainly chorea and dementia. The phenotype of HD is variable and other diseases can have same phenocopy. Therefore gene diagnosis of HD becomes essential for confirmatory diagnosis. Recent discovery of an expanded CAG trinucleotide repeat at the telomeric position of chromosome 4p made the gene diagnosis possible even in sporadic cases. We examined the length of CAG repeat in Huntington gene locus by PCR method in clinically diagnosed HB patients to make a confirmatory diagnosis. METHODS: Three patients with chorea, dementia and family history were tested. All laboratory tests including MRI had been normal so far. Genomic DNA was extracted from their WBC, and PCR was done on Huntington gene locus using primers modified from HD Collaboratory Group. Agarose gel electrophoresis to examine the rough degree of expansion, polyacrylamide gel electrophoresis to determine repeat length, and sequencing of the expanded allele were done. As a second step, three choreic patients without family history, one patient with tardive dyskinesia and one whole HD family were tested. RESULTS: Three choreic patients with family history showed expansion of CAG repeats in the amplified site. Two sporadic choreic patients, and one asymptomatic member in a HD family had increased CAG repeats. CONCLUSION: We confirmed expansion of CAG repeats in Huntington gene locus in clinically diagnosed HD. None of the patients had caudate atrophy, which has been considered an early finding. Sporadic choreic patients could be diagnosed as HD by gene study. Presymptomatic case was found in a family screening, and will need to be followed. Gene analysis offers a critical tool to make a confirmatory diagnosis of HD, and will be a powerful tool in genetic counseling.