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At least 613 records · Page 34Linked to original sources
PubMed1994

The tuberous sclerosis gene on chromosome 9q34 acts as a growth suppressor.

We have previously demonstrated allele loss in hamartomas from patients with tuberous sclerosis for markers spanning the tuberous sclerosis gene on chromosome 16q13.3 (TSC2). Germline deletions in the TSC2 gene have been shown in 5% of patients with tuberous sclerosis (TSC). These data support our hypothesis that the TSC2 gene acts as a growth suppressor gene, analogous to the traditional tumour suppressor gene. We now report a TSC hamartoma showing allele loss for markers on chromosome 9q34 in the region of the TSC1 gene. We studied six hamartomas from four sporadic and two familial cases of TSC, none of which showed allele loss for markers on chromosome 16p13.3. The hamartomas were paraffin embedded sections of three renal angiomyolipomas, two giant cell astrocytomas, and a cardiac rhabdomyoma. Eight markers were analysed, comprising from centromeric to telomeric ASS-D9S64-D9S149-ABO-D9S150-DBH-D9S66-D9S67++ +. One angiomyolipoma showed allele loss for the markers ABO, DBH and D9S66, but not for D9S149 or D9S67. The patient was not informative for D9S150. The family structure did not permit the phase of the disease and marker alleles to be determined. These finding support the hypothesis that the TSC1 gene on 9q34, like the TSC2 gene, acts as a growth suppressor. The data would place the TSC1 gene between D9S149 and D9S67. Mapping of allele loss in hamartomas may help in the refinement of the location of the TSC1 locus.

Angiomyolipoma↗
PubMed1997

Female germline mosaicism in tuberous sclerosis confirmed by molecular genetic analysis.

We have investigated a family in which three siblings with the autosomal dominant disorder tuberous sclerosis had unaffected parents. The family were typed for polymorphic markers spanning the two genes known to cause tuberous sclerosis located at 9q34 (TSC1) and 16p13.3 (TSC2). TSC1 markers showed different maternal and paternal haplotypes in affected children, excluding a mutation in TSC1 as the cause of the disease. For the TSC2 markers all the affected children had the same maternal and paternal haplotypes, as did three of their unaffected siblings. Mutation screening by RT-PCR and direct sequencing of the TSC2 gene identified a 4 bp insertion TACT following nucleotide 2077 in exon 18 which was present in the three affected children but not in five unaffected siblings or the parents. This mutation would cause a frameshift and premature termination at codon 703. Absence of the mutation in lymphocyte DNA from the parents was consistent with germline mosaicism and this was confirmed by our finding of identical chromosome 16 haplotypes in affected and unaffected siblings, providing unequivocal evidence of two different cell lines in the gametes. Molecular analysis of the TSC2 alleles present in the affected subjects showed that the mutation had been inherited from the mother. This is the first case of germline mosaicism in tuberous sclerosis proven by molecular genetic analysis and also the first example of female germline mosaicism for a characterized autosomal dominant gene mutation apparently not associated with somatic mosaicism.

Adult↗
PubMed2006

The influence of cytosolic phosphorylating glyceraldehyde 3-phosphate dehydrogenase (GAPC) on potato tuber metabolism.

The aim of this work was to investigate the importance of cytosolic phosphorylating glyceraldehyde 3-phosphate dehydrogenase (GAPC) in potato carbohydrate metabolism. For this purpose, the cytosolic isoform of phosphorylating GAPC was cloned and used for an antisense approach to generate transgenic potato plants that exhibited constitutively decreased GAPDH activity. Potato lines with decreased activities of phosphorylating GAPC exhibited no major changes in either whole-plant or tuber morphology. However, the levels of 3-phosphoglycerate were decreased in leaves of the transformants. A broad metabolic phenotyping of tubers from the transformants revealed an increase in sucrose and UDPglucose content, a decrease in the glycolytic intermediates 3-phosphoglycerate and phosphoenolpyruvate but little change in the levels of other metabolites. Moreover, the transformants displayed no differences in cold sweetening with respect to the wild type. Taken together these data suggest that phosphorylating GAPC plays only a minor role in the regulation of potato metabolism. The results presented here are discussed in relation to current models regarding primary metabolism in the potato tuber parenchyma.

Biomass↗
PubMed1998

Apparent renal cell carcinomas in tuberous sclerosis are heterogeneous: the identification of malignant epithelioid angiomyolipoma.

Renal epithelial tumors (carcinoma and oncocytoma) have been reported with higher a frequency than expected in patients with the tuberous sclerosis complex. However, the recent identification of a monotypic, epithelioid variant of angiomyolipoma, closely simulating renal cell carcinoma, has cast doubt on the real frequency of carcinoma. Immunohistochemical analysis with a panel of antibodies, including melanogenesis marker HMB45, can discriminate between carcinoma and carcinoma-like angiomyolipoma. We studied five tumors previously reported as carcinoma and found that only one of them showed an immunohistochemical phenotype indicative of an epithelial tumor (Ker+, HMB45-). Three tumors exhibited a phenotype compatible with the monotypic epithelioid variant of angiomyolipoma (HMB45+, Ker-), and two of the three patients died of metastatic disease. The last patient had unusual clinical features, and the tumor was positive both for HMB45 and keratin. It is concluded that (1) renal cell carcinoma is less common in tuberous sclerosis complex than previously believed, (2) some cases called renal cell carcinoma probably represent a monotypic, epithelioid variant of angiomyolipoma, and (3) epithelioid angiomyolipoma is a potentially malignant tumor with invasion and metastases. These findings indicate that all reported renal carcinomas in tuberous sclerosis complex, therefore, must be reevaluated.

Adenoma, Oxyphilic↗
PubMed2001

Treatment of facial angiofibromas of tuberous sclerosis by shave excision and dermabrasion in a dark-skinned patient.

Tuberous sclerosis is an inherited disease expressed clinically by the triad of mental retardation, seizures, and tuberous lesions. Facial angiofibromas, a common manifestation of tuberous sclerosis, can cause considerable cosmetic disfigurement, emotional distress, obstruction of vision, and hemorrhage. Treatment by shave excision, as the first step to remove the larger nodules, followed by dermabrasion, to smooth and sculpt the final surface, has been recommended as the most effective form of therapy. However, this method of treatment raises the question of risk for development of hypopigmentation in susceptible patients. The authors present their treatment of angiofibromas with shave excision and dermabrasion in a dark-skinned patient.

Adult↗
PubMed1991

Tc-99m HMPAO SPECT imaging of the central nervous system in tuberous sclerosis.

Tc-99m HMPAO was used to evaluate cerebral perfusion in a patient with tuberous sclerosis. The SPECT images demonstrated reduced HMPAO uptake in regions corresponding with MRI-confirmed locations of cortical tubers. These results indicate that the lesions are characterized by vascular perfusion deficits and support the hypothesis that cortical tubers result from developmental abnormalities of the embryonic central nervous system.

Brain↗
PubMed2001

Tc-99m HDP bone scan showing bone changes in a case of tuberous sclerosis or Bourneville's disease.

Whole-body Tc-99m HDP scintigraphy was performed in a 25-year-old woman with known tuberous sclerosis. The scintigraphic pattern showed multiple foci of abnormal activity over the hands, phalanges, feet, tibias, fibulas, ulnas, and radii, where radiographs showed periosteal apposition, irregular cortical thickening, and cystlike lesions on the phalanges. The spine, pelvis, and ribs showed heterogeneous tracer uptake where radiographs showed patchy areas of increased bone density. This radiographic pattern is characteristic of osseous tuberous sclerosis. Although previous reports suggested the opposite conclusion, this observation indicates that an abnormal result of bone scintiscan can be observed in osseous tuberous sclerosis.

Adult↗
PubMed1997

Cerebral arterial ectasia and tuberous sclerosis: case report.

OBJECTIVE AND IMPORTANCE: Tuberous sclerosis is associated with a wide variety of central nervous system abnormalities. Cerebrovascular anomalies are extremely rare, but a case of cerebral arterial ectasia and giant fusiform aneurysm formation in a young child is reported. CLINICAL PRESENTATION: A 5-month-old male patient with tuberous sclerosis presented with seizures, a subependymal tumor, and intraventricular hemorrhage. Cerebral angiography demonstrated a large fusiform aneurysm of the left cavernous internal carotid artery as well as arterial ectasia of the proximal left anterior cerebral and middle cerebral arteries. The patient developed hydrocephalus and died of infectious complications after repeated shunt procedures. CONCLUSION: Tuberous sclerosis is commonly associated with central nervous system lesions. Although rare, cerebrovascular anomalies and aneurysms should be considered in the differential diagnosis of mass lesions to avoid an ill-advised biopsy of a vascular lesion, which could have disastrous consequences.

Cerebral Angiography↗
PubMed2001

Bilateral resective epilepsy surgery in a child with tuberous sclerosis: case report.

OBJECTIVE AND IMPORTANCE: Surgical intervention can reduce the burden of seizures in selected patients with tuberous sclerosis and medically refractory epilepsy. CLINICAL PRESENTATION: A child presented with tuberous sclerosis and severe epilepsy beginning in the first month of life and delayed development before 1 year of age. Video-electroencephalographic monitoring at the age of 1 year revealed a left temporal seizure focus. Repeat videoelectroencephalography at 2 years of age revealed a right posterior quadrant seizure focus. Bilateral subdural electrodes were placed, confirming independent seizure onsets from the right parietal area (overlying a tuber) and prominent interictal activity over the left superior temporal region. INTERVENTION: The right parietal focus was resected, and electrodes were maintained over the left temporal focus. After right parietal resection, ictal discharges were recorded over the left temporal region; a corticectomy was performed 2 days later. No tonicoclonic or complex partial seizures have occurred during a follow-up period of more than 24 months. Simple partial motor seizures involving the right foot have been reduced by more than 80%, and other simple partial seizures have been eliminated. Postoperatively, there has been marked improvement in the patient's cognitive and motor developmental status. CONCLUSION: In selected patients with bilateral seizure foci involving separate lobes, aggressive bilateral surgery can be safe and effective.

Cognition Disorders↗
PubMed1991

Cosmetic treatment of shagreen patches in selected patients with tuberous sclerosis.

Patients with mild forms of tuberous sclerosis may request cosmetic treatment of skin hamartomas. Treatment may consist of planning of an elevated shagreen patch with a Reese dermatome and/or laser treatment of facial angiofibromas. These precise patients, i.e., patients with a forme fruste of tuberous sclerosis, are more likely to have pulmonary involvement than patients with the usual complete disease form. A chest x-ray should be obtained in these patients to rule out pulmonary involvement. Half the patients with pulmonary involvement of tuberous sclerosis die an avoidable death from spontaneous pneumothoraces. Positive-pressure ventilation during anesthesia in these patients should be avoided or monitored closely.

Adult↗
PubMed1993

Giant cell astrocytoma of the retina in tuberous sclerosis.

The clinical and pathologic features of an unusual retinal glioma that was the only clinically overt manifestation of tuberous sclerosis in a 27-year-old woman are reported. The tumor was composed predominantly of large pleomorphic cells with glassy eosinophilic cytoplasm. Immunologic staining yielded positive results for gamma enolase, but not for glial fibrillary acid protein. The histologic and immunopathologic features of this tumor were essentially identical to the subependymal giant cell astrocytoma found in tuberous sclerosis. This case illustrates the large overlap in dysplastic astrocytic and neuronal differentiation that can occur in the retina of patients with tuberous sclerosis. Giant cell astrocytoma of the retina can be mistaken for a malignant tumor histologically by persons unfamiliar with this entity.

Adult↗
PubMed1978

Tuberous sclerosis in old age.

A case of tuberous sclerosis without seizures in a 64-year-old man has been presented. Typical cutaneous, retinal, and bone lesions were found, along with calcifications in the lateral and third ventricle. Tuberous sclerosis is generally seen in young patients, though its occurrence in elderly patients has been described in the literature. Diagnosis in the present case was delayed. It is hoped that reemphasis of this aspect of tuberous sclerosis will lead to a prompt diagnosis in similar cases.

Age Factors↗
PubMed1982

Leaf-shaped lesions of ocular fundus and white eyelashes in tuberous sclerosis.

A 5-year-old white girl with tuberous sclerosis had, in addition to bilateral retinal hamartomas, two hypopigmented leaf-shaped areas in the right fundus. These areas may be akin to the well known ash-leaf white cutaneous macules of tuberous sclerosis. Also, poliosis circumscripta was present in the left upper eyelid. Both findings may be rare associated signs of tuberous sclerosis.

Child, Preschool↗
PubMed2000

Pigmentary disorders: update on neurofibromatosis-1 and tuberous sclerosis.

Pigmentary disorders are a common finding in primary care pediatric practice. Tuberous sclerosis and neurofibromatosis type 1 are two pigmentary disorders that have had many changes in their diagnostic and therapeutic approach. This review focuses on the significant advances in the past few years in the genetics and diagnostic criteria of these disorders. A review of the clinical presentation of neurofibromatosis is provided along with the revised diagnostic criteria for tuberous sclerosis. A logical approach to testing the tuberous sclerosis patient and his or her family is included.

Brain Neoplasms↗
PubMed2005

Cutaneous angiomyolipomas are HMB45 negative, not associated with tuberous sclerosis, and should be considered as angioleiomyomas with fat.

Angiomyolipomas are uncommon tumors in the skin. Neoplasms with the same name are more typically associated with a renal location, many in the context of tuberous sclerosis. Three cases of cutaneous angiomyolipoma are reported, which were all HMB45 negative and not associated with tuberous sclerosis. This is the first series of such tumors to be stained with HMB45. The presence of fat in histologically similar cutaneous angioleiomyomas has been previously documented and a review of 40 archival cases revealed fat in 1 case. The author proposes that cutaneous angiomyolipomas should be termed angioleiomyoma with fat to avoid confusion with unrelated non-cutaneous angiomyolipomas that are HMB45 negative and require investigation for tuberous sclerosis.

Adipose Tissue↗
PubMed2004

Repression of a novel isoform of disproportionating enzyme (stDPE2) in potato leads to inhibition of starch degradation in leaves but not tubers stored at low temperature.

A potato (Solanum tuberosum) cDNA encoding an isoform of disproportionating enzyme (stDPE2) was identified in a functional screen in Escherichia coli. The stDPE2 protein was demonstrated to be present in chloroplasts and to accumulate at times of active starch degradation in potato leaves and tubers. Transgenic potato plants were made in which its presence was almost completely eliminated. It could be demonstrated that starch degradation was repressed in leaves of the transgenic plants but that cold-induced sweetening was not affected in tubers stored at 4 degrees C. No evidence could be found for an effect of repression of stDPE2 on starch synthesis. The malto-oligosaccharide content of leaves from the transgenic plants was assessed. It was found that the amounts of malto-oligosaccharides increased in all plants during the dark period and that the transgenic lines accumulated up to 10-fold more than the control. Separation of these malto-oligosaccharides by high-performance anion-exchange chromatography with pulsed-amperometric detection showed that the only one that accumulated in the transgenic plants in comparison with the control was maltose. stDPE2 was purified to apparent homogeneity from potato tuber extracts and could be demonstrated to transfer glucose from maltose to oyster glycogen.

Chloroplasts↗
PubMed2006

Management of cutaneous angiomyolipoma and its association with tuberous sclerosis.

Although typically presenting renally, angiomyolipomas can rarely present in the skin. The tumors are composed of an admixture of blood vessels, smooth muscle and adipose tissue and are often seen in the setting of tuberous sclerosis. We describe a case of angiomyolipoma presenting on the thigh of a 50-year-old white female. This is the 17th reported case of cutaneous angiomyolipoma. As with all previously described cases, our patient did not present with the stigmata of tuberous sclerosis. Angiomyolipoma should be considered within the differential for subcutaneous nodules and work-up for tuberous sclerosis should not be pursued when presenting in the skin.

Angiomyolipoma↗
PubMed1993

Development, behaviour and seizures in 300 cases of tuberous sclerosis.

Three hundred cases of tuberous sclerosis were surveyed by postal questionnaire, including 240 cases with learning difficulties. People who have tuberous sclerosis and severe learning disabilities also have a higher frequency of epileptic seizures than people with learning difficulties from all causes. Pervasive developmental disorder and hyperactive behaviour are behavioural features of the disorder. Sleep problems and the level of vigilant care required because of seizures or behaviour have implications on the level of service needed to support people with tuberous sclerosis in the community.

Adolescent↗