The gene for Machado-Joseph disease maps to human chromosome 14q.

Machado-Joseph disease (MJD) is an autosomal dominant, multisystem neurodegenerative disorder involving predominantly cerebellar, pyramidal, extrapyramidal, motor neuron and oculomotor systems. Although it was first reported in families of Portuguese-Azorean descent, MJD has also been described in non-Azorean families from various countries, being one of the most common hereditary spinocerebellar degenerations. With the use of highly polymorphic microsatellite DNA polymorphisms, we have assigned the gene for MJD to the long arm of chromosome 14 (14q24.3-q32) by genetic linkage to microsatellite loci D14S55 and D14S48 (multipoint lod score Zmax = 9.719).

Early-onset ataxia with ocular motor apraxia and hypoalbuminemia is caused by mutations in a new HIT superfamily gene.

Friedreich ataxia (FRDA), the most common autosomal recessive neurodegenerative disease among Europeans and people of European descent, is characterized by an early onset (usually before the age of 25), progressive ataxia, sensory loss, absence of tendon reflexes and pyramidal weakness of the legs. We have recently identified a unique group of patients whose clinical presentations are characterized by autosomal recessive inheritance, early age of onset, FRDA-like clinical presentations and hypoalbuminemia. Linkage to the FRDA locus, however, was excluded. Given the similarities of the clinical presentations to those of the recently described ataxia with oculomotor apraxia (AOA) linked to chromosome 9p13, we confirmed that the disorder of our patients is also linked to the same locus. We narrowed the candidate region and have identified a new gene encoding a member of the histidine triad (HIT) superfamily as the 'causative' gene. We have called its product aprataxin; the gene symbol is APTX. Although many HIT proteins have been identified, aprataxin is the first to be linked to a distinct phenotype.

Expanded polyglutamine stretches interact with TAFII130, interfering with CREB-dependent transcription.

At least eight inherited neurodegenerative diseases are caused by expanded CAG repeats encoding polyglutamine (polyQ) stretches. Although cytotoxicities of expanded polyQ stretches are implicated, the molecular mechanisms of neurodegeneration remain unclear. We found that expanded polyQ stretches preferentially bind to TAFII130, a coactivator involved in cAMP-responsive element binding protein (CREB)-dependent transcriptional activation, and strongly suppress CREB-dependent transcriptional activation. The suppression of CREB-dependent transcription and the cell death induced by polyQ stretches were restored by the co-expression of TAFII130. Our results indicate that interference of transcription by the binding of TAFII130 with expanded polyQ stretches is involved in the pathogenetic mechanisms underlying neurodegeneration.

Identification of the spinocerebellar ataxia type 2 gene using a direct identification of repeat expansion and cloning technique, DIRECT.

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant, neurodegenerative disorder that affects the cerebellum and other areas of the central nervous system. We have devised a novel strategy, the direct identification of repeat expansion and cloning technique (DIRECT), which allows selective detection of expanded CAG repeats and cloning of the genes involved. By applying DIRECT, we identified an expanded CAG repeat of the gene for SCA2. CAG repeats of normal alleles range in size from 15 to 24 repeat units, while those of SCA2 chromosomes are expanded to 35 to 59 repeat units. The SCA2 cDNA is predicted to code for 1,313 amino acids-with the CAG repeats coding for a polyglutamine tract. DIRECT is a robust strategy for identification of pathologically expanded trinucleotide repeats and will dramatically accelerate the search for causative genes of neuropsychiatric diseases caused by trinucleotide repeat expansions.

Reduction of both beta cell death and alpha cell proliferation by dipeptidyl peptidase-4 inhibition in a streptozotocin-induced model of diabetes in mice.

AIMS/HYPOTHESIS: Incretins stimulate insulin secretion in a glucose-dependent manner but also promote pancreatic beta cell protection. Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new glucose-lowering treatment that blocks incretin degradation by DPP-4. We assessed whether DPP-4 inhibition suppresses the progression to hyperglycaemia in a low-dose streptozotocin (STZ)-induced diabetic mouse model, and then investigated how DPP-4 inhibition affects islet function and morphology. METHODS: The DPP-4 inhibitor, des-fluoro-sitagliptin (SITA), was administered to mice during and after STZ injections, and in some mice also before STZ. RESULTS: In control mice, STZ resulted in hyperglycaemia associated with impaired insulin secretion and excess glucagon secretion. In SITA-treated STZ mice, these metabolic abnormalities were improved, particularly when SITA administration was initiated before STZ injections. We observed beta cell loss and dramatic alpha cell expansion associated with decreased insulin content and increased glucagon content after STZ administration. In SITA-treated mice, islet architecture and insulin content were preserved, and no significant increase in glucagon content was observed. After STZ exposure, beta cell apoptosis increased before hyperglycaemia, and SITA treatment reduced the number of apoptotic beta cells. Interestingly, alpha cell proliferation was observed in non-treated mice after STZ injection, but the proliferation was not observed in SITA-treated mice. CONCLUSIONS/INTERPRETATION: Our results suggest that the ability of DPP-4 inhibition to suppress the progression to STZ-induced hyperglycaemia involves both alleviation of beta cell death and alpha cell proliferation.

Novel SACS mutation in a Belgian family with sacsin-related ataxia.

The authors describe the four patients in the first known Belgian family with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). A novel homozygous missense mutation, NM_014363.3: c.3491T>A in exon 9, of the SACS gene was identified in the present family, which results in an original amino acid of methionine to lysine substitution at amino acid residue 1164 (p.M1164K). Although the cardinal clinical features, i.e., spastic ataxia with peripheral neuropathy, in our patients were similar to those in Quebec patients, our patients exhibited some atypical clinical features, e.g., teenage-onset and absence of retinal hypermyelination. The present family is from Wallonia, and there could be shared ethnicity with the families of Charlevoix-Saguenay.

16q-linked autosomal dominant cerebellar ataxia: a clinical and genetic study.

The autosomal dominant cerebellar ataxias (ADCAs) comprise a genetically and clinically heterogenous group of neurodegenerative disorders. Very recently, a C-to-T single nucleotide substitution in the puratrophin-1 gene was found to be strongly associated with a form of ADCA linked to chromosome 16q22.1 (16q-linked ADCA; OMIM 600223). We found the C-to-T substitution in the puratrophin-1 gene in 20 patients with ataxia (16 heterozygotes and four homozygotes) and four asymptomatic carriers in 9 of 24 families with an unknown type of ADCA. We also found two cases with 16q-linked ADCA among 43 sporadic patients with late-onset cortical cerebellar atrophy (LCCA). The mean age at onset in the 22 patients was 61.8 years, and that of homozygous patients was lower than that of heterozygous ones in one family. Neurological examination revealed that the majority of our patients showed exaggerated deep tendon reflexes in addition to the cardinal symptom of cerebellar ataxia (100%), and 37.5% of them had sensorineural hearing impairment, whereas sensory axonal neuropathy was absent. The frequency of 16q-linked ADCA was about 1/10 of our series of 110 ADCA families, making it the third most frequent ADCA in Japan.

Expression of blood group-related antigens ABH, Lewis A, Lewis B, Lewis X, Lewis Y, and CA 19-9 in pancreatic cancer cells in comparison with the patient's blood group type.

Blood group A, B, H, Le, Leb, Lex, and Ley antigenicity as well as the expression of CA 19-9 were examined in pancreatic cancer specimens from 30 patients, using monoclonal antibodies to the respective antigen and immunohistochemical techniques, and the findings were correlated with the blood group types (ABO and Lewis) of the individuals. Compatible antigen expression was found in 82, 75, and 50% of tumors from patients with A, B, and O blood group types, respectively. Deletion of the compatible antigen was found in 10 (33%) of the cases, predominantly in patients of blood group O type, and incompatible expression (of B antigen only) in 4 (13%). Lea was detected in 87%, Leb in 90%, Lex in 30%, and Ley in 43% of the specimens, regardless of ABH and Lewis phenotype of the patients. Coexpression of Lea and Leb was found in 87%, of Lex and Ley in 13%, of Lea and Lex in 23%, and of Leb and Ley in 40% of the cases. CA 19-9 was expressed in 80% of the tumors; it was present in the tumor tissue of 21 of 22 patients from Lea-b+, in all 4 individuals from Lea+b-, but in none of the 4 patients from Lea-b- phenotype (P less than 0.01). Heterogeneity in the expression of each of the antigens was found. The overall results indicate that blood group antigen expression in pancreatic tumor differs from that of other gastrointestinal cancers and that the Lewis antigen expression in pancreatic cancer cells is independent of the blood group phenotype of the patients and thus may be useful as a tumor marker.

The effects of hydrocortisone and RU486 (mifepristone) on iodide uptake in porcine thyroid cells in primary culture.

The effects of hydrocortisone on iodide uptake and DNA synthesis were studied in porcine thyroid cells cultured in phenol red-free medium supplemented with low concentrations (0-1%) of charcoal-stripped fetal calf serum. Hydrocortisone dose-dependently stimulated TSH-induced iodide uptake at physiological concentrations (1-1000 nM), and the minimum detectable dose was 33 nM hydrocortisone. Treatment of thyroid cells with hydrocortisone for 72 h increased cAMP production stimulated by TSH. In addition, this stimulatory effect of hydrocortisone was observed when iodide uptake was induced with 0.25 mM 8-bromo-cAMP. These results suggest that hydrocortisone stimulates iodide uptake, influencing cAMP production and post-cAMP pathways. The synthetic glucocorticoid antagonist RU486 alone had no effect on iodide uptake in porcine thyroid cells; however, along with TSH, RU486 a weak agonist activity. As a glucocorticoid antagonist, RU486 inhibited the stimulatory actions of hydrocortisone on iodide uptake in combination with TSH and also with 8-bromo-cAMP, suggesting a specific effect of hydrocortisone mediated by a glucocorticoid receptor. The effect of hydrocortisone on thyroid cell multiplication was also studied. Hydrocortisone decreased [3H]thymidine incorporation into DNA slightly but not significantly when the cells were treated with 100 ng/ml insulin-like growth factor-I and hydrocortisone. In summary, it has been demonstrated that hydrocortisone directly stimulated the function of porcine thyroid cells at physiological concentrations, by using a glucocorticoid receptor and by affecting cAMP pathways. The data that RU486 inhibited iodide uptake induced by hydrocortisone and TSH propose that monitoring of thyroid function may be necessary if RU486 is been used for a long time.

Thyroid-specific expression of cholera toxin A1 subunit causes thyroid hyperplasia and hyperthyroidism in transgenic mice.

Thyroid cell growth and function are regulated by hormones and growth factors binding to cell surface receptors that are coupled via G proteins, Gs and Gq, to the adenylyl cyclase and phospholipase C signal transduction systems, respectively. Activating mutations of the TSH receptor and G alpha s have been documented in subsets of thyroid neoplasms. To test the oncogenic potential of activated G alpha s in transgenic mice, we used the cholera toxin A1 subunit that constitutively activates G alpha s and used the rat thyroglobulin gene promoter for targeting this transgene (TGCT) to thyroid follicular cells. Three (M1392, F1358, and F1286) of six founders identified were able to transmit the transgene to their offspring and thyroid glands from these mice contained elevated levels of cAMP. Concentrations of serum thyroxine were elevated as early as 2 months of age (M 1392 and F 1286). F1358 mice were euthyroid until 8 months of age, at which time they developed hyperthyroidism. All three TGCT lines developed thyroid hyperplasia independent of their thyroxine levels. DNA image analysis of thyroid follicular cells from both the hyper and euthyroid mice showed that DNA index and "S+G2/M" phase were increased compared with normal, changes similar to that seen in poor prognosis human carcinomas. These data suggest that the G alpha s-adenylyl cyclase-cAMP pathway has an important role in thyroid hyperplasia and the transgenic mouse models reported herein will allow further examination of the role of this pathway in thyroid oncogenesis.

Polymerase chain reaction-based microsatellite polymorphism analysis of follicular and Hürthle cell neoplasms of the thyroid.

Follicular and Hürthle cell carcinomas of the thyroid cannot be differentiated from adenomas by either preoperative fine needle aspiration or intraoperative frozen section examination, and yet there exist potentially significant differences in the recommended surgical management. We examined, by PCR-based microsatellite polymorphism analysis, DNA obtained from 83 thyroid neoplasms [22 follicular adenomas, 29 follicular carcinomas, 20 Hürthle cell adenomas (HA), and 12 Hürthle cell carcinomas (HC)] to determine whether a pattern of allelic alteration exists that could help distinguish benign from malignant lesions. Alterations were found in only 7.5% of informative PCR reactions from follicular neoplasms, whereas they were found in 23.3% of reactions from Hürthle cell neoplasms. Although there were no significant differences between follicular adenoma and follicular carcinoma, HC demonstrated a significantly greater percentage of allelic alteration than HA on chromosomal arms 1q (P < 0.001) and 2p (P < 0.05) by Fisher's exact test. The documentation of an alteration on either 1q or 2p was 100% sensitive and 65% specific in the detection of HC (P < 0.0005, by McNemar's test). In conclusion, PCR-based microsatellite polymorphism analysis may be a useful technique in distinguishing HC from HA. Potentially, the application of this technique to aspirated material may allow this distinction preoperatively and thus facilitate more optimal surgical management. Consistent regions of allelic alteration may also indicate the locations of critical genes, such as tumor suppressor genes or oncogenes, that are important in the progression from adenoma to carcinoma. Finally, this study demonstrates that Hürthle cell neoplasms, now considered variants of follicular neoplasms, differ significantly from follicular neoplasms on a molecular level.

Spinocerebellar ataxia type 1 in China: molecular analysis and genotype-phenotype correlation in 5 families.

BACKGROUND: Twelve genetic types of autosomal dominant hereditary ataxia have been recently identified and the genes responsible for most of them cloned. Molecular identification of the type of ataxia is important to determine the disease prevalence and its natural history in various populations. OBJECTIVES: To perform molecular analysis of 75 Chinese families affected with spinocerebellar ataxia (SCA) and to evaluate the spectrum of mutations in these genes and the correlation between genotypes and phenotypes in Chinese patients. SETTING: Neurogenetics Unit, China-Japan Friendship Hospital, Beijing, China. METHODS: One hundred nine patients from 75 kindreds diagnosed as having autosomal dominant SCA, 16 patients with sporadic SCA or spastic paraplegia, 280 control chromosomes of the Chinese population, and 120 control chromosomes of the Sakha population were selected for this study. We conducted detailed mutational analysis by direct sequencing of polymerase chain reaction products amplified from genomic DNA. RESULTS: Spinocerebellar ataxia type 1 (SCA1) was identified in 5 families with 12 studied patients. All affected family members were heterozygous for a CAG repeat expansion in the SCA1 gene containing 51 to 64 trinucleotide repeats. Normal alleles had 26 to 35 repeats. Spinocerebellar ataxia type 1 accounted for 7% of the studied Chinese families with ataxia. In addition, we determined the frequency of a single vs double CAT interruption in 120 control chromosomes of the Siberian Sakha population, which has the highest known prevalence of SCA1, and compared this with 280 control chromosomes from the Chinese populations. The results show that 64.7% of the Siberian normal alleles contain a single CAT interruption, whereas 92% of the Chinese had more than 1 interruption. CONCLUSIONS: Spinocerebellar ataxia type 1 is responsible for 7% of affected families in the Chinese population. A correlation between the prevalence of SCA1 and the number of CAT interruptions in the trinucleotide chain suggests that a CAT-to-CAG substitution may have been the initial event contributing to the generation of expanded alleles and influencing relative prevalence of SCA1.

Machado-Joseph disease: cerebellar ataxia and autonomic dysfunction in a patient with the shortest known expanded allele (56 CAG repeat units) of the MJD1 gene.

We describe an unusual case of a patient with Machado-Joseph disease (MJD) who showed autonomic dysfunctions in addition to cerebellar ataxia. The number of CAG repeat units in the expanded allele of the MJD1 gene of the patient is smaller (56 CAG repeat units) than all previously reported numbers of CAG repeat units in expanded alleles. Thus, the findings in this patient indicate that the clinical features of MJD cover a wider spectrum than previously thought.

Neuronal hyperexcitability in stroke-like episodes of MELAS syndrome.

BACKGROUND: The pathogenesis of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) remains unknown. METHODS: Fourteen stroke-like episodes in six patients with MELAS were studied using clinical, neuroradiologic, and electrophysiologic approaches. In two patients postmortem examination was done. RESULTS: Headache and epileptic seizure were the most common presenting symptoms. In 13 of 14 episodes the cerebral cortex was primarily involved with variable subcortical edema particularly in the temporal, occipital, and parietal cortex. Repeated MRI performed in two episodes revealed progressive spread of the cortical lesion to the surrounding cortex for a few weeks after the onset of symptoms. In 6 of 11 episodes T1-weighted hyperintense cortical signal compatible with cortical laminar necrosis was seen during subacute stage of the episode. Fat-suppression MRI confirmed intracortical gyral hemorrhage in one episode. Petechial gyral microhemorrhages were also pathologically confirmed in the autopsy of another patient. In 9 of 11 episodes focal epileptiform discharges on EEG were noted in the acute brain lesion. In seven of nine episodes focal cortical hyperperfusion was seen in SPECT studies. CONCLUSION: The stroke-like episodes in MELAS may reflect neuronal hyperexcitability, which increases energy demand and creates energy imbalance between energy requirement and adequate availability of adenosine triphosphate due to oxidative phosphorylation defect particularly in the susceptible neuronal population, causing cortical necrosis. The episodic nature of stroke-like episodes is unexplained.

A clinical and pathologic study of a large Japanese family with Machado-Joseph disease tightly linked to the DNA markers on chromosome 14q.

The gene locus for Machado-Joseph disease (MJD) has been mapped to chromosome 14q by linkage analysis, mainly using a single large Japanese family. We studied the clinical and neuropathologic findings of this family with MJD, comparing them with those of spinocerebellar ataxia 1 (SCA1) and spinocerebellar ataxia 2 (SCA2) families. The pedigree included 30 affected persons in 125 members of five generations. Neurologic examination of 21 patients revealed that dystonia, difficulty in eyelid opening, slowness of movements, bulging eyes, and facial-lingual fasciculation-like movements or myokymia are characteristic of this MJD family, although these three autosomal dominant spinocerebellar degenerations have several neurologic signs and symptoms in common. In contrast with SCA1 and SCA2, degeneration of the subthalamopallidal system and relative sparing of the olivocerebellar system were the main neuropathologic features of MJD.

Early-onset ataxia with ocular motor apraxia and hypoalbuminemia: the aprataxin gene mutations.

BACKGROUND: Early-onset ataxia with hypoalbuminemia is regarded as a variant form of Friedreich ataxia in Japan. Early-onset ataxia with hypoalbuminemia and ataxia with ocular motor apraxia have been considered as the same clinical entity because of the recent identification of a common mutation in the aprataxin gene. A new clinical entity named early-onset ataxia with ocular motor apraxia and hypoalbuminemia (EAOH) has been proposed to explain these two diseases. OBJECTIVE: To disclose the clinical features of EAOH and to identify the mutations in the aprataxin gene in six patients in four Japanese families with EAOH. METHODS: The clinical features, laboratory findings, sural nerve biopsy results, and brain MRI or CT findings for these patients were evaluated, and molecular analysis was performed, which involved sequencing of the aprataxin gene directly or use of the subcloning method. RESULTS: Cerebellar ataxia and peripheral neuropathy were noted in all six patients. Ocular motor apraxia was observed in five patients; two of these patients had obvious head thrust. Choreiform movements of the limbs and mental deterioration were observed in five patients. Although foot deformity was noted in five patients, kyphoscoliosis was noted only in one patient. In all patients, hypoalbuminemia and hypercholesterolemia were evident, and brain MRI or CT showed marked cerebellar atrophy. Nerve biopsy revealed depletion of large myelinated fibers in three of the five patients examined. Molecular analysis of the aprataxin gene revealed an insertion mutation (insT at nt167) and two missense mutations (A-to-G transition at nt80 and C-to-T transition at nt95, the former being novel). CONCLUSION: We found clinical heterogeneity in the patients with EAOH in this study. With the disease course, the choreiform movements tended to reduce in degree, and hypoalbuminemia became evident. Molecular analysis identified one insertion and two missense mutations including a novel missense one, which was located at a highly conserved amino acid residue in the aprataxin gene product.

Machado-Joseph disease in four Chinese pedigrees: molecular analysis of 15 patients including two juvenile cases and clinical correlations.

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder associated with the expansion of a (CAG)n array in the MJD1 gene. We analyzed the sizes of the (CAG)n array using DNA samples from 61 members of four Chinese MJD families and 18 Chinese normal control subjects and confirmed that the (CAG)n array in 15 MJD chromosomes was expanded to 72-86 repeat units. There were no subjects with (CAG)n array sizes intermediate between those of normal and MJD affected groups. Meanwhile, we found a significant negative correlation between the age of onset of symptoms and (CAG)n array size. The largest (CAG)n array of 86 repeat units was in the youngest patient, whose age of onset was 5 years. The intergenerational increase in number of CAG repeat units was associated with the clinical phenomenon of anticipation.

Co-expression of CA 19-9, DU-PAN-2, CA 125, and TAG-72 in pancreatic adenocarcinoma.

Various tumor-associated antigens have been reported in pancreatic adenocarcinoma tissue. This study examines the incidence and co-expression of CA 19-9, DU-PAN-2, CA 125, and TAG-72 in serum and cancer tissue from patients with pancreatic cancer. In tissue, 83% of the cases demonstrated co-expression of three or more antigens. The incidence of antigen expression was comparably high for CA 19-9, DU-PAN-2, and TAG-72; however, significantly more cancer cells within each sample demonstrated CA 19-9. Serologic co-expression of elevated antigen levels was less common; only 39% of the patients showed increased circulating levels of three or more antigens. The predictive value of tissue immunoreactivity for elevated circulating levels of antigen was strongest for CA 19-9. Immunoreactivity patterns in cancer tissue suggest that the epitopes for these antigens are distinct, and DU-PAN-2 antigen was identified in patients who could not manufacture CA 19-9 (a sialylated Lea antigen). However, a strong correlation between circulating levels of CA 19-9 and DU-PAN-2 supports the contention that these two antigens are incidentally expressed on the same mucin molecule.

Induction of multifocal pancreatic cancer after inoculation of hamster pancreatic cancer cell line (PC-1) into a defined area of homologous pancreatic tissue.

Inoculation of the pancreatic cancer cell line PC-1 into a defined area of the tail of the hamster pancreas led to development of multiple cancerous foci in the body of the pancreas along the main pancreatic duct. Each carcinoma showed identical histological characteristics and was completely separated from the others by regions of normal pancreatic tissue. This observation suggests spread of the cancer from the primary site in discontinuity through the ductal system of the pancreas.