Cellular and molecular characterization of two novel asparagine synthetase gene mutations linked to asparagine synthetase deficiency.

Asparagine synthetase (ASNS) catalyzes synthesis of asparagine (Asn) and Glu from Asp and Gln in an ATP-dependent reaction. Asparagine synthetase deficiency (ASNSD) results from biallelic mutations in the ASNS gene. Affected children exhibit congenital microcephaly, continued brain atrophy, seizures, and often premature mortality. However, the underlying mechanisms are unclear. This report describes a compound heterozygotic ASNSD child with two novel mutations in the ASNS gene, c.1118G>T (paternal) and c.1556G>A (maternal), that lead to G373V or R519H ASNS variants. Structural mapping suggested that neither variant participates directly in catalysis. Growth of cultured fibroblasts from either parent was unaffected in Asn-free medium, whereas growth of the child's cells was suppressed by about 50%. Analysis of Asn levels unexpectedly revealed that extracellular rather than intracellular Asn correlated with the reduced proliferation during incubation of the child's cells in Asn-free medium. Our attempts to ectopically express the G373V variant in either HEK293T or JRS cells resulted in minimal protein production, suggesting instability. Protein expression and purification from HEK293T cells revealed reduced activity for the R519H variant relative to WT ASNS. Expression of WT ASNS in ASNS-null JRS cells resulted in nearly complete rescue of growth in Asn-free medium, whereas we observed no proliferation for the cells expressing either the G373V or R519H variant. These results support the conclusion that the coexpression of the G373V and R519H ASNS variants leads to significantly reduced Asn synthesis, which negatively impacts cellular growth. These observations are consistent with the ASNSD phenotype.

Adjunctive everolimus therapy for tuberous sclerosis complex-associated refractory seizures: Results from the postextension phase of EXIST-3.

OBJECTIVE: Epilepsy is highly prevalent in patients with tuberous sclerosis complex (TSC). Everolimus showed higher efficacy than placebo for seizures in the primary analysis of the EXIST-3 study. Here, we present the long-term outcomes of everolimus at the end of the postextension phase (PEP; data cutoff date: October 25, 2017). METHODS: After completion of the extension phase, patients were invited to continue everolimus in the PEP with everolimus (targeted trough concentration = 5-15 ng/ml, investigator-judged). Efficacy assessments included changes in seizure status during the PEP collected at 12-week intervals as parent/caregiver-reported data through a structured questionnaire. RESULTS: Among 361 patients, 343 entered the extension phase and 249 entered the PEP. After 12 weeks in the PEP, 18.9% (46/244) of patients were seizure-free since the last visit of the extension phase and 64.8% (158/244) had a stable/improved seizure status. At 24 weeks, the corresponding percentages were 18.2% (42/231) and 64.5% (149/231). Among 244 patients, the response rate was 32.8% (80/244) during the 12-week maintenance period of the core phase and 63.9% (156/244) at the end of the extension phase. Of the 149 responders at the end of the extension phase, 70.5% were seizure-free or had stable/improved seizure status. Long-term efficacy data showed persistent responses were observed in 183 of 361 patients (50.7%); 63.9% of these patients had a response that lasted at least 48 weeks. The most frequent Grade 3-4 adverse events (≥2% incidence) reported throughout the study were pneumonia, status epilepticus, seizure, stomatitis, neutropenia, and gastroenteritis. Four patients died during the study. SIGNIFICANCE: The final analysis of EXIST-3 demonstrated the sustained efficacy of everolimus as adjunctive therapy in patients with TSC-associated treatment-refractory seizures, with a tolerable safety profile.

Effect of everolimus on renal function in patients with tuberous sclerosis complex: evidence from EXIST-1 and EXIST-2.

BACKGROUND: A reduction in renal angiomyolipoma volume observed with everolimus (EVE) treatment in patients with tuberous sclerosis complex (TSC) has been postulated to translate to clinical benefit by reducing the risk of renal hemorrhage and chronic renal failure. METHODS: The long-term effects of EVE on renal function (∼4 years of treatment) were examined in patients treated with EVE in the Phase 3 EXIST-1 and EXIST-2 studies. Patients in EXIST-1 had TSC and subependymal giant cell astrocytoma (SEGA), and patients in EXIST-2 had renal angiomyolipoma and a definite diagnosis of TSC or sporadic lymphangioleiomyomatosis. EVE was administered at 4.5 mg/m2/day, with adjustment to achieve target trough levels of 5-15 ng/mL in EXIST-1 and at 10 mg/day in EXIST-2. Estimated glomerular filtration rate (eGFR) and creatinine levels were assessed at baseline, at Weeks 2, 4, 6, 8, 12 and 18, then every 3 months thereafter. Proteinuria was graded according to National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0. RESULTS: A total of 111 patients from EXIST-1 and 112 patients from EXIST-2 were included in this analysis. Respective mean ages at EVE initiation were 10.5 [standard deviation (SD) 6.45] and 33.2 (SD 10.29) years, and 3.6% and 37.5% of patients had undergone prior renal intervention. Mean baseline eGFR was 115 and 88 mL/min/1.73 m2 in EXIST-1 and EXIST-2, respectively. Overall, mean eGFR remained stable over time in both studies, with an decline in renal function mostly confined to some patients with severely compromised renal function before treatment. Patients with prior renal intervention exhibited low eGFR values throughout the study. The incidence of proteinuria increased after initiating treatment with EVE and was mostly Grade 1/2 in severity, with Grade 3 proteinuria reported in only two patients. Measurements of proteinuria were limited by the use of urine dipstick tests. CONCLUSIONS: The use of EVE does not appear to be nephrotoxic in patients with SEGA or renal angiomyolipoma associated with TSC and may preserve renal function in most patients.ClinicalTrials.gov identifiers NCT00789828 and NCT00790400.

Everolimus dosing recommendations for tuberous sclerosis complex-associated refractory seizures.

OBJECTIVE: The present analysis examined the exposure-response relationship by means of the predose everolimus concentration (Cmin ) and the seizure response in patients with tuberous sclerosis complex-associated seizures in the EXIST-3 study. Recommendations have been made for the target Cmin range of everolimus for therapeutic drug monitoring (TDM) and the doses necessary to achieve this target Cmin . METHODS: A model-based approach was used to predict patients' daily Cmin . Time-normalized Cmin (TN-Cmin ) was calculated as the average predicted Cmin in a time interval. TN-Cmin was used to link exposure to efficacy and safety end points via model-based approaches. A conditional logistic regression stratified by age subgroup was used to estimate the probability of response in relation to exposure. A multiplicative linear regression model was used to estimate the exposure-response relationship for seizure frequency (SF). An extended Cox regression model was used to link exposure to the time to first adverse event. RESULTS: There was a strong, consistent, and highly significant relationship between everolimus exposure and efficacy, measured by TN-Cmin and SF, regardless of patient's age and concomitant use of cytochrome P450 3A4 (CYP3A4) inhibitors/inducers. Results of an extended Cox regression analyses indicated that twofold increases in TN-Cmin were not associated with statistically significant increases in the risk of stomatitis or infections. SIGNIFICANCE: The recommended TDM is to target everolimus Cmin within a range of 5-7 ng/mL initially and 5-15 ng/mL in the event of an inadequate clinical response, and safety is consistent with previous reports. Starting doses depend on age and the concomitant use of CYP3A4/P-glycoprotein inducers/inhibitors.

The effect of everolimus on renal angiomyolipoma in pediatric patients with tuberous sclerosis being treated for subependymal giant cell astrocytoma.

BACKGROUND: Patients with tuberous sclerosis complex (TSC) often have multiple TSC-associated hamartomas, particularly in the brain and kidney. METHODS: This was a post hoc analysis of pediatric patients being treated for subependymal giant cell astrocytomas (SEGAs) during the phase 3, randomized, double-blind, placebo-controlled EXIST-1 trial. Patients were initially randomly assigned to receive everolimus 4.5 mg/m2/day (target blood trough 5-15 mg/dl) or placebo and could continue in an open-label extension phase. Angiomyolipoma response rates were analyzed in patients aged <18 years with ≥1 target angiomyolipoma lesion at baseline. Response was defined as the proportion of patients with a ≥50% reduction in the sum volume of target renal angiomyolipomata from baseline, in the absence of new target angiomyolipomata, a >20% increase in kidney volume from nadir, and angiomyolipoma-related bleeding ≥ grade 2. Tolerability was also assessed. RESULTS: Overall, this analysis included 33 patients. Renal angiomyolipoma response was achieved by 75.8% of patients (95% confidence interval, 57.7-88.9%), with sustained mean reductions in renal angiomyolipoma volume over nearly 4 years of treatment. In addition, most (≥80%) achieved clinically relevant reductions in angiomyolipoma volume (≥50%), beginning at week 24 and continuing for the remainder of the study. Everolimus was generally well tolerated in this subgroup, with most adverse events being grade 1 or 2 in severity. CONCLUSIONS: Although everolimus is currently not indicated for this use, this analysis from EXIST-1 demonstrates its long-term efficacy and safety for the treatment of renal angiomyolipoma in pediatric patients undergoing treatment for TSC-associated SEGA.

Thoracoabdominal imaging of tuberous sclerosis.

Imaging of tuberous sclerosis complex has rapidly evolved over the last decade in association with increased understanding of the disease process and new treatment modalities. Tuberous sclerosis complex is best known for the neurological symptoms and the associated neuroimaging findings, and children with tuberous sclerosis complex require active surveillance of associated abnormalities in the chest, abdomen and pelvis. Common findings that require regular imaging surveillance are angiomyolipomas in the kidneys and lymphangioleiomyomatosis in the chest. However multiple rarer associations have been attributed to tuberous sclerosis complex and should be considered by radiologists reviewing any imaging in these children. In this review the authors discuss the spectrum of imaging findings in people with tuberous sclerosis complex, focusing on MR imaging findings in the chest, abdomen and pelvis.

Mosaic and Intronic Mutations in TSC1/TSC2 Explain the Majority of TSC Patients with No Mutation Identified by Conventional Testing.

Tuberous sclerosis complex (TSC) is an autosomal dominant tumor suppressor gene syndrome due to germline mutations in either TSC1 or TSC2. 10-15% of TSC individuals have no mutation identified (NMI) after thorough conventional molecular diagnostic assessment. 53 TSC subjects who were NMI were studied using next generation sequencing to search for mutations in these genes. Blood/saliva DNA including parental samples were available from all subjects, and skin tumor biopsy DNA was available from six subjects. We identified mutations in 45 of 53 subjects (85%). Mosaicism was observed in the majority (26 of 45, 58%), and intronic mutations were also unusually common, seen in 18 of 45 subjects (40%). Seventeen (38%) mutations were seen at an allele frequency < 5%, five at an allele frequency < 1%, and two were identified in skin tumor biopsies only, and were not seen at appreciable frequency in blood or saliva DNA. These findings illuminate the extent of mosaicism in TSC, indicate the importance of full gene coverage and next generation sequencing for mutation detection, show that analysis of TSC-related tumors can increase the mutation detection rate, indicate that it is not likely that a third TSC gene exists, and enable provision of genetic counseling to the substantial population of TSC individuals who are currently NMI.

Adjunctive everolimus therapy for treatment-resistant focal-onset seizures associated with tuberous sclerosis (EXIST-3): a phase 3, randomised, double-blind, placebo-controlled study.

BACKGROUND: Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been used for various benign tumours associated with tuberous sclerosis complex. We assessed the efficacy and safety of two trough exposure concentrations of everolimus, 3-7 ng/mL (low exposure) and 9-15 ng/mL (high exposure), compared with placebo as adjunctive therapy for treatment-resistant focal-onset seizures in tuberous sclerosis complex. METHODS: In this phase 3, randomised, double-blind, placebo-controlled study, eligible patients aged 2-65 years with tuberous sclerosis complex and treatment-resistant seizures (≥16 in an 8-week baseline phase) receiving one to three concomitant antiepileptic drugs were recruited from 99 centres across 25 countries. Participants were randomly assigned (1:1:1), via permuted-block randomisation (block size of six) implemented by Interactive Response Technology software, to receive placebo, low-exposure everolimus, or high-exposure everolimus. Randomisation was stratified by age subgroup (<6 years, 6 to <12 years, 12 to <18 years, and ≥18 years). Patients, investigators, site personnel, and the sponsor's study team were masked to treatment allocation. The starting dose of everolimus depended on age, body-surface area, and concomitant use of cytochrome 3A4/P-glycoprotein inducers. Dose adjustments were done to attain target trough ranges during a 6-week titration period, and as needed during a 12-week maintenance period of core phase. Patients or their caregivers recorded events in a seizure diary throughout the study. The primary endpoint was change from baseline in the frequency of seizures during the maintenance period, defined as response rate (the proportion of patients achieving ≥50% reduction in seizure frequency) and median percentage reduction in seizure frequency, in all randomised patients. This study is registered with ClinicalTrials.gov, number NCT01713946. FINDINGS: Between July 3, 2013, and May 29, 2015, 366 patients were enrolled and randomly assigned to placebo (n=119), low-exposure everolimus, (n=117), or high-exposure everolimus (n=130). The response rate was 15·1% with placebo (95% CI 9·2-22·8; 18 patients) compared with 28·2% for low-exposure everolimus (95% CI 20·3-37·3; 33 patients; p=0·0077) and 40·0% for high-exposure everolimus (95% CI 31·5-49·0; 52 patients; p<0·0001). The median percentage reduction in seizure frequency was 14·9% (95% CI 0·1-21·7) with placebo versus 29·3% with low-exposure everolimus (95% CI 18·8-41·9; p=0·0028) and 39·6% with high-exposure everolimus (95% CI 35·0-48·7; p<0·0001). Grade 3 or 4 adverse events occurred in 13 (11%) patients in the placebo group, 21 (18%) in the low-exposure group, and 31 (24%) in the high-exposure group. Serious adverse events were reported in three (3%) patients who received placebo, 16 (14%) who received low-exposure everolimus, and 18 (14%) who received high-exposure everolimus. Adverse events led to treatment discontinuation in two (2%) patients in the placebo group versus six (5%) in the low-exposure group and four (3%) in the high-exposure group. INTERPRETATION: Adjunctive everolimus treatment significantly reduced seizure frequency with a tolerable safety profile compared with placebo in patients with tuberous sclerosis complex and treatment-resistant seizures. FUNDING: Novartis Pharmaceuticals Corporation.

Improvement in Renal Cystic Disease of Tuberous Sclerosis Complex After Treatment with Mammalian Target of Rapamycin Inhibitor.

Renal cysts occur in approximately 50% of patients with tuberous sclerosis complex, but their clinical significance and response to treatment are unknown. Abdominal imaging of 15 patients with tuberous sclerosis complex-associated renal cystic disease who had received mammalian target of rapamycin inhibitor therapy for other tuberous sclerosis complex-related indications was evaluated. Reductions in cyst number, sum diameter, and volume were observed.

Everolimus for subependymal giant cell astrocytoma: 5-year final analysis.

OBJECTIVE: To analyze the cumulative efficacy and safety of everolimus in treating subependymal giant cell astrocytomas (SEGA) associated with tuberous sclerosis complex (TSC) from an open-label phase II study (NCT00411619). Updated data became available from the conclusion of the extension phase and are presented in this ≥5-year analysis. METHODS: Patients aged ≥ 3 years with a definite diagnosis of TSC and increasing SEGA lesion size (≥2 magnetic resonance imaging scans) received everolimus starting at 3mg/m(2) /day (titrated to target blood trough levels of 5-15ng/ml). The primary efficacy endpoint was reduction from baseline in primary SEGA volume. RESULTS: As of the study completion date (January 28, 2014), 22 of 28 (78.6%) initially enrolled patients finished the study per protocol. Median (range) duration of exposure to everolimus was 67.8 (4.7-83.2) months; 12 (52.2%) and 14 (60.9%) of 23 patients experienced SEGA volume reductions of ≥50% and ≥30% relative to baseline, respectively, after 60 months of treatment. The proportion of patients experiencing daily seizures was reduced from 7 of 26 (26.9%) patients at baseline to 2 of 18 (11.1%) patients at month 60. Most commonly reported adverse events (AEs) were upper respiratory tract infection and stomatitis of mostly grade 1 or 2 severity. No patient discontinued treatment due to AEs. The frequency of emergence of most AEs decreased over the course of the study. INTERPRETATION: Everolimus continues to demonstrate a sustained effect on SEGA tumor reduction over ≥5 years of treatment. Everolimus remained well-tolerated, and no new safety concerns were noted.

The effect of everolimus on renal angiomyolipoma in patients with tuberous sclerosis complex being treated for subependymal giant cell astrocytoma: subgroup results from the randomized, placebo-controlled, Phase 3 trial EXIST-1.

BACKGROUND: Tuberous sclerosis complex (TSC) is characterized by benign tumours in multiple organs, including the brain, kidneys, skin, lungs and heart. Our objective was to evaluate everolimus, an mTOR inhibitor, in the treatment of angiomyolipoma in patients with subependymal giant cell astrocytoma (SEGA) associated with TSC. METHODS: EXamining everolimus In a Study of Tuberous Sclerosis Complex-1 (NCT00789828), a prospective, double-blind, randomized, placebo-controlled, Phase 3 study, examined everolimus in treating SEGA associated with TSC. Patients with serial SEGA growth from pre-baseline to baseline scans were randomly assigned (2:1) to receive 4.5 mg/m(2)/day everolimus (target blood trough: 5-15 ng/mL; n = 78) or placebo (n = 39). Angiomyolipoma response rates were analysed in patients (n = 44) with target baseline angiomyolipoma lesions (≥1 angiomyolipoma; longest diameter ≥1.0 cm). An angiomyolipoma response rate, defined as the proportion of patients with confirmed angiomyolipoma response, was assessed by kidney CT or MRI screening at baseline, at 12, 24 and 48 weeks and annually. RESULTS: Angiomyolipoma response rates were 53.3% (16/30) and 0% (0/14) for everolimus- and placebo-treated patients, respectively. Angiomyolipoma reductions ≥50% in the sum of volumes of all target lesions were seen only in everolimus-treated patients (56.5, 78.3 and 80.0%) compared with placebo-treated patients (0% at each time point) at Weeks 12, 24 and 48, respectively. Greater percentages of everolimus-treated patients had angiomyolipoma reductions ≥30% at these same time points (82.6, 100 and 100% versus 8.3, 18.2 and 16.7% for everolimus versus placebo, respectively). CONCLUSIONS: Everolimus showed efficacy in reducing angiomyolipoma lesion volume in patients with SEGA associated with TSC.The trial is registered with ClinicalTrials.gov, number NCT00789828; http://clinicaltrials.gov/ct2/show/NCT00789828?term=EXIST-1&rank=1.

Cenobamate's Efficacy for Seizure Treatment in Tuberous Sclerosis Complex.

BACKGROUND: Epilepsy is prevalent, and seizure control is challenging in patients with tuberous sclerosis complex (TSC). Cenobamate (CBM) has proven efficacy in several studies; however, its benefit in the TSC population is not known. METHODS: We performed a retrospective review of patients with TSC who received adjunctive CBM for seizure treatments. We assessed treatment efficacy by comparing seizure frequencies three months before CBM (baseline) and those at 3-, 6-, 12-, and 18- month follow-ups. RESULTS: We identified 70 patients with TSC receiving CBM and excluded 16 with insufficient data. Fifty-four patients aged 2 to 39 years, with an average baseline seizure of 66.1 ± 88.9 per month, were analyzed. Treatment retention rates at 3, 6, 12, and 18 months were 94.4%, 79.6%, 66.7%, 44.4%, and responder rates (proportions of patients who remained on treatment and had ≥50% seizure reduction) were 38.1%, 51.7%, 53.1%, and 59.1%, respectively. Seizure-free rates at these respective follow-ups were 7.1%, 13.8%, 6.3%, and 9.1%. For patients experiencing reduced seizures, the mean percentage of change ranged from 61.5% to 74.6%. Side effects were common (64.8%), particularly sedation (42.6%), behavioral disturbance (24.1%), and gastrointestinal disturbance (22.2%). CONCLUSIONS: Most patients in this study showed seizure reduction; however, the overall responder and seizure-free rates were lower than the literature, likely due to the unique underlying epileptogenesis in TSC and the challenges of tolerating CBM. The lower treatment retention rates signal areas for improvement in concurrent medication adjustment practices.

Stiripentol in Dravet syndrome: results of a retrospective U.S. study.

PURPOSE: To review the efficacy and tolerability of stiripentol in the treatment of U.S. children with Dravet syndrome. METHODS: U.S. clinicians who had prescribed stiripentol for two or more children with Dravet syndrome between March 2005 and 2012 were contacted to request participation in this retrospective study. Data collected included overall seizure frequency, frequency of prolonged seizures, and use of rescue medications and emergency room (ER)/hospital visits in the year preceding stiripentol initiation, and with stiripentol therapy. We separately assessed efficacy in the following treatment groups: group A, stiripentol without clobazam or valproate; group B, stiripentol with clobazam but without valproate; group C, stiripentol with valproate but without clobazam; and group D, stiripentol with clobazam and valproate. In addition, adverse effects were recorded. KEY FINDINGS: Thirteen of 16 clinicians contacted for study participated and provided data on 82 children. Stiripentol was initiated a median of 6.0 years after seizure onset and 1.2 years after diagnosis of Dravet syndrome. Compared to baseline, overall seizure frequency was reduced in 2/6 in group A, 28/35 in group B, 8/14 in group C, and 30/48 in group D. All children with prolonged seizure frequency greater than quarterly during the baseline period experienced a reduction in this frequency on the various treatment arms with stiripentol. Similarly, 2/4 patients in group A, 25/25 in group B, 5/10 in group C, and 26/33 in group D experienced reduction in frequency of rescue medication use and 1/1 in group A, 12/12 in group B, 3/5 in group C, and 18/19 in group D had reduction in frequency of ER/hospital visits. Adverse effects were reported in 38, most commonly sedation and reduced appetite. Four patients (5%) discontinued stiripentol for adverse effects and two (2%) for lack of efficacy. SIGNIFICANCE: Stiripentol is an effective and well-tolerated therapy that markedly reduced frequency of prolonged seizures in Dravet syndrome.

Stiripentol for Drug-Resistant Epilepsy Treatment in Tuberous Sclerosis Complex.

BACKGROUND: Drug-resistant epilepsy (DRE) is common in tuberous sclerosis complex (TSC). The role of stiripentol (STP) in seizure treatment in this population is not well understood. This study evaluates the efficacy and tolerability of STP in patients with TSC with DRE. METHODS: We performed a retrospective review of patients with TSC with DRE. Seizure frequencies at 1 month before (baseline) and 1, 3, 6, and 12 months after STP initiation were collected. RESULTS: Of the 1492 patients, 13 received STP and the number of patients with ≥50% seizure reduction at 1, 3, 6, and 12 months was 6/13 (46.2%), 4/13 (30.8%), 8/13 (61.5%), and 6/13 (46.2%), respectively. Six patients (46.2%) had favorable outcomes with persistent seizure reduction through 12 months. Their mean (±S.D.) percentage of seizure reduction at 1, 3, 6, and 12 months was 68.1 (±22.0), 71.3 (±23.2), 75.7 (±23.5), and 75.7 (±23.5), respectively. One patient had worsening seizures throughout the STP course. Three patients did not have seizure reduction until after 6 months, and 2 had initial seizure reduction before worsening. Younger age (P value <0.001), early STP treatment (P value <0.001), higher doses (P value = 0.004), and higher baseline seizure frequency (P value = 0.01) were associated with favorable outcomes. Side effects were seen in 85% of our cohort. CONCLUSIONS: About 46% of the patients had favorable outcomes. Younger age, early STP treatment, higher doses, and higher baseline seizure frequency were significantly associated with favorable outcomes.

Prevalence of thoracoabdominal imaging findings in tuberous sclerosis complex.

BACKGROUND: Tuberous sclerosis complex (TSC) results in neurodevelopmental phenotypes, benign tumors, and cysts throughout the body. Recent studies show numerous rare findings in TSC. Guidelines suggest routine abdominal and chest imaging to monitor these thoracoabdominal findings, but imaging is not uniformly done across centers. Thus, the prevalence of many findings is unknown. To answer this, we categorized the clinical reads of 1398 thoracoabdominal scans from 649 patients of all ages in the Cincinnati Children's Hospital TSC Repository Database. RESULTS: Typical TSC findings were present in many patients: kidney cysts (72%), kidney fat-containing angiomyolipomas (51%), kidney lipid-poor angiomyolipomas (27%), liver angiomyolipomas (19%), and lung nodules thought to represent multifocal micronodular pneumocyte hyperplasia (MMPH) (18%). While many features were more common in TSC2 patients, TSC1 patients had a higher prevalence of MMPH than TSC2 patients (24% versus 13%, p = 0.05). Many rare findings (e.g., lymphatic malformations and liver masses) are more common in TSC than in the general population. Additionally, most thoracoabdominal imaging findings increased with age except kidney cysts which decreased, with the 0-10 years age group having the highest percentage (69% 0-10 years, 49% 10-21 years, 48% 21 + years, p < 0.001). Finally, in our population, no patients had renal cell carcinoma found on abdominal imaging. CONCLUSIONS: These results show that regular thoracoabdominal scans in TSC may show several findings that should not be ignored or, conversely, over-reacted to when found in patients with TSC. Female sex, TSC2 mutation, and age are risk factors for many thoracoabdominal findings. The data suggest novel interactions of genetic mutation with pulmonary nodules and age with renal cysts. Finally, in agreement with other works, these findings indicate that several rare thoracoabdominal imaging findings occur at higher rates in the TSC population than in the general population. This work supports obtaining detailed thoracoabdominal imaging in patients with TSC.

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.)

Diabetes in Individuals With Tuberous Sclerosis Complex Treated With mTOR Inhibitors.

BACKGROUND: Tuberous sclerosis complex (TSC) is a genetic disorder that is manifested in multiple body systems. A mammalian target of rapamycin (mTOR) inhibitor (mTORi), either everolimus or sirolimus, is now routinely prescribed for multiple clinical manifestations of TSC, including subependymal giant cell astrocytoma and epilepsy. These medications are generally well tolerated. Side effects previously identified in well-designed clinical trials tend to be mild and readily manageable. Regulatory approvals for the treatment of TSC have expanded the use of everolimus and sirolimus clinically, enlarging clinician experience and enabling identification of potential treatment-related effects that are rarer than could be identified or recognized in previous clinical trials. METHODS: The medical records of clinical patients from our TSC center who were treated with an mTORi and later developed diabetes mellitus (DM) were analyzed and compared with those who were not treated with an mTORi. Eight individuals received detailed analysis, including laboratory results, concomitant medications, and body mass indices. RESULTS: Among the 1576 individuals with TSC, 4% taking an mTORi developed diabetes compared with 0.6% of those not on mTORi, showing a significant interaction between DM and mTORi (chi-square = 18.1, P < 0.001). Details of eight patients who developed DM were presented. CONCLUSIONS: The long-term use of mTORi agents in TSC may contribute to a risk of diabetes. Early detection can be critical in management. Additional studies are need to further investigate a causal relationship, but clinicians should be aware of this possible association when initiating and monitoring ongoing treatment.

RHOA signaling defects result in impaired axon guidance in iPSC-derived neurons from patients with tuberous sclerosis complex.

Patients with Tuberous Sclerosis Complex (TSC) show aberrant wiring of neuronal connections formed during development which may contribute to symptoms of TSC, such as intellectual disabilities, autism, and epilepsy. Yet models examining the molecular basis for axonal guidance defects in developing human neurons have not been developed. Here, we generate human induced pluripotent stem cell (hiPSC) lines from a patient with TSC and genetically engineer counterparts and isogenic controls. By differentiating hiPSCs, we show that control neurons respond to canonical guidance cues as predicted. Conversely, neurons with heterozygous loss of TSC2 exhibit reduced responses to several repulsive cues and defective axon guidance. While TSC2 is a known key negative regulator of MTOR-dependent protein synthesis, we find that TSC2 signaled through MTOR-independent RHOA in growth cones. Our results suggest that neural network connectivity defects in patients with TSC may result from defects in RHOA-mediated regulation of cytoskeletal dynamics during neuronal development.

Symptom rates and profile clustering in tuberous sclerosis complex-associated neuropsychiatric disorders (TAND).

BACKGROUND: Tuberous Sclerosis Complex (TSC) is associated with a range of neuropsychiatric difficulties, appropriately termed TSC-Associated Neuropsychiatric Disorders (TAND). The objectives of the study were to analyze the rates of TAND symptoms in a cohort of patients seen at the TSC Center of Excellence at Cincinnati Children's Hospital and to identify clinically meaningful profiles based on TAND symptoms. METHODS: Data from the TAND Checklist was obtained from participants seen at the TSC Center of Excellence at Cincinnati Children's Hospital Medical Center from June 2015 to August 2018. Cluster and factor analyses for each TAND symptom were performed. Factor scores were then calculated for participants, and a K-means cluster analysis of these scores was used to empirically identify distinct overall TAND symptom profiles occurring in TSC. RESULTS: A total of 1545 checklists was completed for 668 participants (37% adults and 63% children). Approximately 90% of participants reported at least one TAND symptom with an average of 12 symptoms (out of 29). Symptom rates ranged between 5 and 60%. The most common symptoms were neuropsychologic symptoms. A seven-cluster and seven-factor solution were found to be optimal. K-means cluster analysis resulted in a seven-profile solution, ranging from low to high symptom burden. CONCLUSION: This study is the first to identify natural phenotypic profiles of TAND symptoms. Study of specific TAND subpopulations with shared profiles may facilitate better understanding of the underlying biology of TAND and better assessment of more targeted treatments.