Gail Chuck

Sirolimus for Angiomyolipoma in Tuberous Sclerosis Complex or Lymphangioleiomyomatosis

BACKGROUND Angiomyolipomas in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis are associated with mutations in tuberous sclerosis genes resulting in constitutive activation of the mammalian target of rapamycin (mTOR). The drug sirolimus suppresses mTOR signaling. METHODS We conducted a 24-month, nonrandomized, open-label trial to determine whether sirolimus reduces the angiomyolipoma volume in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis. Sirolimus was administered for the first 12 months only. Serial magnetic resonance imaging of angiomyolipomas and brain lesions, computed tomography of lung cysts, and pulmonary-function tests were performed. RESULTS Of the 25 patients enrolled, 20 completed the 12-month evaluation, and 18 completed the 24-month evaluation. The mean (+/-SD) angiomyolipoma volume at 12 months was 53.2+/-26.6% of the baseline value (P<0.001) and at 24 months was 85.9+/-28.5% of the baseline value (P=0.005). At 24 months, five patients had a persistent reduction in the angiomyolipoma volume of 30% or more. During the period of sirolimus therapy, among patients with lymphangioleiomyomatosis, the mean forced expiratory volume in 1 second (FEV1) increased by 118+/-330 ml (P=0.06), the forced vital capacity (FVC) increased by 390+/-570 ml (P<0.001), and the residual volume decreased by 439+/-493 ml (P=0.02), as compared with baseline values. One year after sirolimus was discontinued, the FEV1 was 62+/-411 ml above the baseline value, the FVC was 346+/-712 ml above the baseline value, and the residual volume was 333+/-570 ml below the baseline value; cerebral lesions were unchanged. Five patients had six serious adverse events while receiving sirolimus, including diarrhea, pyelonephritis, stomatitis, and respiratory infections. CONCLUSIONS Angiomyolipomas regressed somewhat during sirolimus therapy but tended to increase in volume after the therapy was stopped. Some patients with lymphangioleiomyomatosis had improvement in spirometric measurements and gas trapping that persisted after treatment. Suppression of mTOR signaling might constitute an ameliorative treatment in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis. (ClinicalTrials.gov number, NCT00457808.)

Rapamycin causes regression of astrocytomas in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a genetic disorder characterized by the formation of hamartomas in multiple organs. Five to 15% of affected individuals display subependymal giant cell astrocytomas, which can lead to substantial neurological and postoperative morbidity due to the production of hydrocephalus, mass effect, and their typical location adjacent to the foramen of Monro. We sought to see whether therapy with oral rapamycin could affect growth or induce regression in astrocytomas associated with TSC.

Irreversible brain creatine deficiency with elevated serum and urine creatine: A creatine transporter defect?

Recent reports highlight the utility of in vivo magnetic resonance spectroscopy (MRS) techniques to recognize creatine deficiency syndromes affecting the central nervous system (CNS). Reported cases demonstrate partial reversibility of neurologic symptoms upon restoration of CNS creatine levels with the administration of oral creatine. We describe a patient with a brain creatine deficiency syndrome detected by proton MRS that differs from published reports. Metabolic screening revealed elevated creatine in the serum and urine, with normal levels of guanidino acetic acid. Unlike the case with other reported creatine deficiency syndromes, treatment with oral creatine monohydrate demonstrated no observable increase in brain creatine with proton MRS and no improvement in clinical symptoms. In this study, we report a novel brain creatine deficiency syndrome most likely representing a creatine transporter defect. Ann Neurol 2001;49:401–404

Deficient activity of dephosphophosphorylase kinase and accumulation of glycogen in the liver

Low activity of phosphorylase and increased concentration of glycogen were found in liver tissue from five children with asymptomatic hepatomegaly. In vitro activation of liver phosphorylase in these patients occurred at the rate of 10% or less of normal. Elimination of the defect by the addition of kinase that activates phosphorylase demonstrated the integrity of the phosphorylase enzyme and the deficient activity of dephophophosphorylase kinase. On the average, 60% of the phosphorylase enzyme of normal human liver was in the active form. Phosphorylase kinase of rabbit muscle activated phosphorylase of normal human liver to a final value that was significantly higher than the one obtained in the absence of muscle phosphorylase kinase. The ultrastructural examination of hepatic tissue from the five patients revealed increased amounts of glycogen. There was scarcity of endoplasmic reticulum. There was intercellular glycogen in continuity with the glycogen of the hepatocytes through breaks in their circumference. Lipid droplets with lucid areas in the form of needles and plates contained aggregates of glycogen. There were numerous lysosomes, some containing glycogen. Large vacuoles filled with glycogen and surrounded by a membrane were seen occasionally. The vacuoles might reflect the lysosomal pathway of glycogen degradation, since there was apparent fusion of such autophagic vacuoles with small vesicles resembling primary lysosomes.

Infantile dilated X-linked cardiomyopathy, G4.5 mutations, altered lipids, and ultrastructural malformations of mitochondria in heart, liver, and skeletal muscle.

Mutations in the Xq28 gene G4.5 lead to dilated cardiomyopathy (DCM). Differential splicing of G4.5 results in a family of proteins called “tafazzins” with homology to acyltransferases. These enzymes assemble fatty acids into membrane lipids. We sequenced G4.5 in two kindreds with X-linked DCM and in two unrelated men, one with idiopathic DCM and the other with DCM of arrhythmogenic right ventricular dysplasia. We examined the ultrastructure of heart, liver, and muscle biopsy specimens in these three DCM types; we used gas chromatography to compare fatty acid composition in heart, liver, and muscle autopsy specimens of two patients of kindred 1 with that of controls. In X-linked DCM, G4.5 had a stop codon (E188X), a nonsense mutation, in kindred 1 and an amino acid substitution (G240R), a missense mutation, in kindred 2. In the two men with isolated DCM, G4.5 was not mutated. Ultrastructural mitochondrial malformations were present in the biopsy tissues of the patients with DCM. Cardiac biopsy specimens of both kindreds with X-linked DCM exhibited greatly enlarged mitochondria with large bundles of stacked, compacted, disarrayed cristae that differed from those of the two types of isolated DCM. Autopsy tissue of patients with X-linked DCM had decreased unsaturated and increased saturated fatty acid concentrations. Seven of 13 published G4.5 missense mutations, including the one presented here, occur in acyltransferase motifs. Impaired acyltransferase function could result in increased fatty acid saturation that would decrease membrane fluidity. Mitochondrial membrane proliferation may be an attempt to compensate for impaired function of acyltransferase. Cardiac ultrastructure separates X-linked DCM with G4.5 mutations from the two types of isolated DCM without G4.5 mutations. Electron microscopy of promptly fixed myocardial biopsy specimens has a role in defining the differential diagnosis of DCM. Mutational analysis of the G4.5 gene also serves this purpose.

Rapid Prenatal Diagnosis of Glycogen-Storage Disease Type II by Electron Microscopy of Uncultured Amniotic-Fluid Cells

Glycogen-storage disease Type IIa is a fatal, genetically determined disease of infancy or early childhood that is characterized by deficient activity of acid alpha-glucosidase and by the presence of intracellular vacuoles full of glycogen, which are found in most tissues, including skin and liver. On electron microscopy these specific vacuoles are tightly packed accumulations of glycogen particles surrounded by a single membrane. We did electron-microscopical examinations on uncultured amniotic-fluid cells from 26 women whose fetuses were at risk for glycogen-storage disease Type IIa and from 8 normal control pregnant women. We found specific vacuoles in cells from 6 of the 26 high-risk patients. At delivery, glycogen-storage disease Type IIa was present in the infants of these 6 women and absent in those of the other 20 according to results of clinical, biochemical, and electron-microscopical studies of gestational products. After amniocentesis at 15 to 18 weeks of gestation, the prenatal diagnosis made by electron microscopy of uncultured amniotic-fluid cells was available in three to six days, whereas it took from three to six weeks to make the diagnosis by enzymatic analysis of the cultured amniotic-fluid cells. We conclude that the electron-microscopical prenatal diagnosis of glycogen-storage disease Type IIa is rapid, safe, and reliable. It should facilitate earlier diagnosis and thereby help to preserve parental options.

Pulmonary Cysts Consistent With Lymphangioleiomyomatosis Are Common in Women With Tuberous Sclerosis: Genetic and Radiographic Analysis

L ymphangioleiomyomatosis (LAM) and multifocal micronodular pneumocyte hyperplasia produce cystic and nodular disease, respectively, in the lungs of patients with tuberous sclerosis (TSC). The objective of this study was to prospectively characterize the prevalence, clinical presentation, and genetic basis of lung disease in TSC. CT scanning of the chest on 23 asymptomatic women with TSC identified cystic or nodular changes in 52%. Cystic pulmonary parenchymal changes consistent with LAM were found in nine patients (39%). These patients tended to be older than cyst-negative patients (31.9 7.6 years vs 24.8 11.6 years, p 0.09), and there was no correlation between presence of cysts and tobacco use, age at menarche, history of pregnancy, or use of estrogen-containing medications. Three of the cyst-positive patients had a prior history of pneumothorax. Pulmonary function studies revealed evidence of gas trapping but normal spirometric indexes in the cyst-positive group. All 9 cyst-positive patients had angiomyolipomas, which were larger (p 0.05) and more frequently required intervention (p 0.08) than cyst-negative patients (8 of 14 patients with angiomyolipomas, p 0.05). Ten patients (43%) had pulmonary parenchymal nodules. Pulmonary nodules were more common in women with cysts (78% vs 21%, p 0.05). TSC2 mutations were identified in all cyst-positive patients who were tested (n 8), while both TSC1 and TSC2 mutations were identified in patients with nodular disease. Correlation of the mutational and radiographic data revealed one pair of sisters who were discordant for cystic disease, two motherdaughter pairs who were discordant for nodular disease, and no clear association between cyst development and a specific mutational type. This prospective analysis demonstrates that cystic and nodular pulmonary changes consistent with LAM and multifocal modular pneumocyte hyperplasia are common in women with TSC.

Presence of normal creatine in the muscle of a patient with a mutation in the creatine transporter: A case study

To date, more than seven families have been reported who carry a mutation in the X-linked creatine-transporter (CrT) gene. The resulting lack of creatine in the brain is associated with mental retardation, severe expressive language disorder, mild epilepsy, and a complete absence of Cr in the brain (measured using MRS). Conversely, these patients had no observable cardiac or musculo-skeletal deficits.In this case study, a 22-year-old patient underwent surgical repair for scoliosis. Proton MRS of this patients brain demonstrated the near-absence of creatine and phosphocreatine within the cerebral white and deep gray matter structures. Cerebral atrophy was noted with serial MRI examinations. Subsequent genetic and metabolic analysis showed some biochemical anomalies consistent with a CrT deficiency. The mutation in this patient was identified as a deletion at phenylalanine 107 (delF107). Control muscle biopsies were obtained from archived samples, which had been taken with informed consent during routine muscle biopsies for diagnostic purposes. We determined that the total Cr concentration in the skeletal muscle biopsy was 39.3 ± 2.94 mmol/kg wet wt., which is not significantly different from non-CrT controls, n= 3 (43.3 ± 3.57 mmol/kg wet wt.).We conclude that the brain appears to lack the ability to transport creatine when there is a mutation in the CrT gene. However, the muscle utilizes another mechanism for maintaining normal creatine levels. Identifying this alternative creatine-transport mechanism may be useful in treating the neurologic and cognitive impairments of patients with creatine-transporter deficiency. (Mol Cell Biochem 262: 35–39, 2004)

Levetiracetam as adjunctive antiepileptic therapy for patients with tuberous sclerosis complex: a retrospective open-label trial.

Seizures are a common neurologic symptom of tuberous sclerosis complex. The use of levetiracetam as adjunctive antiepileptic therapy was assessed in 20 patients with tuberous sclerosis complex aged 2 to 19 years. In this retrospective evaluation, 40% of patients treated with levetiracetam achieved a seizure reduction of more than 50%. Levetiracetam was generally well tolerated, and adverse events were relatively uncommon in patients who responded to treatment. The most commonly reported adverse events were behavioral problems. Unstable gait, insomnia, poor appetite, and increased seizure frequency were also reported. Based on these results, the use of levetiracetam as adjunctive antiepileptic therapy can reduce seizure frequency in patients with tuberous sclerosis complex. (J Child Neurol 2006;21:53—57).

Alpha 1 -Antitrypsin Phenotype: Transient Cathodal Shift in Serum of Infant Girl with Urinary Cytomegalovirus and Fatty Liver

Summary: A 2-month-old white girl had severe liver disease (but without signs of hepatic necrosis, infection or cirrhosis), urinary cytomegalovirus, transient reduction of α1-antitrypsin concentration and transient abnormal α1-antitrypsin phenotype that were not present in her parents. Five serum specimens that were obtained during the 1½ months of acute phase liver disease indicated, by polyacrylamide gel isoelectric focusing (PAG-IEF), acid starch gel and agarose electrophoresis as well as immunofixation, an unusual α1-antitrypsin phenotype that we labeled delta (Δ). It migrated adjacent to Z, i.e., cathodal of Z and Zpratt on PAG-IEF; anodal of Z but cathodal of X, S, Zpratt on starch gel. We labeled the girls complete phenotype MΔ. After clinical recovery, her phenotype was MM and identical to that of her parents. Hepatic electron-microscopy of the acute phase specimen showed dilated bile canaliculi. We observed the following in hepatocytes: clusters of globular inclusions surrounded by myelin sheets that, to a lesser extent, also appeared in the liver of CMV-infected children with phenotype MM; dilated endoplasmic reticulum cisternae that contained floccular material; and marked steatosis. These changes were less severe in the convalescent liver specimen.Speculation: The patients transient α1-antitrypsin Δ protein may be the result of a postribosomal reduction in sialic acid of M protein triggered perhaps by sever liver disease. If so, we would not expect a further cathodal shift of Pi type Δ after treatment of MΔ serum with neuraminidase. Alternatively, Δ protein might be the product of an α1-antitrypsin allele PiΔ that was transiently activated by the stress of the liver disease as is the juvenile globin gene in the adult goat by erythropoietic stress. The argument for PiΔ would be strengthened if: (1) the identical Δ protein was found in patients with other severe diseases of the liver; (2) the primary structure of Δ protein differed from that of M protein; (3) the material within the cisternae of the patients hepatocytes was related to α1-anti-trypsin; and (4) neuraminidase treatment of MΔ serum was followed by a further cathodal shift of Pi type Δ.