Treatment of Cardiac Rhabdomyomas with mTOR Inhibitors in Children with Tuberous Sclerosis Complex-A Systematic Review

Exploring Cardiovascular Involvement in Tuberous Sclerosis: Insights for Pediatric Clinicians

Tuberous sclerosis is a rare genetic disorder involving mainly the nervous and cardiovascular systems. The early recognition of the cardiovascular manifestations by the pediatrician allows an appropriate management and therefore enhances the quality of life of the affected children. Cardiac rhabdomyomas and the associated arrhythmias are the first cardiac features and they might represent a diagnosis challenge given their wide spectrum of clinical manifestations. We aimed to provide the paediatric practitioners with current knowledge regarding the cardiovascular complications in children with tuberous sclerosis. We overviewed the antenatal and postnatal evolution of cardiovascular manifestations, the systematic screening and long-term follow-up strategy of cardiac rhabdomyomas and arrhythmias in children with tuberous sclerosis.

Cardiac Rhabdomyomas Presenting with Critical Cardiac Obstruction in Neonates and Infants: Treatment Strategies and Outcome, A Single-Center Experience

Cardiac rhabdomyomas are the most common benign pediatric heart tumor in infancy, which are commonly associated with tuberous sclerosis complex (TSC). Most rhabdomyomas are asymptomatic and spontaneously regress over time. However, some cases especially in neonates or small infants can present with hemodynamic instability. Surgical resection of the tumor, which has been the gold standard in alleviating obstruction, is not always possible and may be associated with significant morbidity and mortality. Recently, mammalian target of rapamycin inhibitors (mTORi) have been shown to be safe and effective in the treatment of TSC. We present the outcomes of neonates and an infant who received treatment for symptomatic rhabdomyomas at a tertiary cardiology center. Medical records were reviewed to obtain clinical, demographic, and outcome data. Six patients received interventions for symptomatic rhabdomyomas, median age at presentation was 1 day old (range from 1 to 121 days old), and 67% of the patients had a pathogenic mutation in TSC gene. One patient underwent surgical resection of solitary tumor at right ventricular outflow tract (RVOT) successfully. In the four patients with left ventricular outflow tract (LVOT) obstruction, two patients received combined therapy of surgical debulking of LVOT tumor, Stage I palliation procedure, and mTORi and two patients received mTORi therapy. One patient with RVOT obstruction underwent ductal stenting and received synergistic mTORi. Four of the five patients had good response to mTORi demonstrated by the rapid regression of rhabdomyoma size. 83% of patients are still alive at their latest follow-up, at two to eight years of age. One patient died on day 17 post-LVOT tumor resection and Hybrid stage one due to failure of hemostasis, in the background of familial factor VII deficiency. Treatment of symptomatic rhabdomyoma requires individualized treatment strategy based on the underlying pathophysiology, with involvement of multidisciplinary teams. mTORi is effective and safe in inducing rapid regression of rhabdomyomas. A standardized mTORi prescription and monitoring guide will ensure medication safety in neonates and infants with symptomatic cardiac rhabdomyoma. Although the majority of tumors responded to mTORi, some prove to be resistant. Further studies are warranted, ideally involving multiple international centers with a larger number of patients.

Long-term use of everolimus for refractory arrhythmia in a child with tuberous sclerosis complex

Tuberous sclerosis complex is associated with the occurrence of cardiac rhabdomyomas that may result in life-threatening arrhythmia unresponsive to standard antiarrhythmic therapy. We report the case of an infant with multiple cardiac rhabdomyomas who developed severe refractory supraventricular tachycardia (SVT) that was successfully treated with everolimus. Pharmacological mTOR inhibition rapidly improved arrhythmia within few weeks after treatment initiation and correlated with a reduction in tumor size. Intermediate attempts to discontinue everolimus resulted in rhabdomyoma size rebound and recurrence of arrhythmic episodes, which resolved on resumption of therapy. While everolimus treatment led to successful control of arrhythmia in the first years of life, episodes of SVT reoccurred at the age of 6 years. Electrophysiologic testing confirmed an accessory pathway that was successfully ablated, resulting in freedom of arrhythmic events. In summary we present an in-depth evaluation of the long-term use of everolimus in a child with TSC-associated SVT, including the correlation between drug use and arrhythmia outcome. This case report provides important information on the safety and efficacy of an mTOR inhibitor for the treatment of a potentially life-threatening cardiac disease manifestation in TSC for which the optimal treatment strategy is still not well established.

Safety and efficacy of sirolimus in recurrent intravenous leiomyomatosis, pulmonary benign metastatic leiomyomatosis, and leiomyomatosis peritonealis disseminata: a pilot study

BACKGROUND

Intravenous leiomyomatosis (IVL), pulmonary benign metastatic leiomyomatosis (PBML), and leiomyomatosis peritonealis disseminata (LPD) are leiomyomas with special growth patterns and high postoperative recurrence rates. We report the safety and efficacy of a pilot study of sirolimus in the treatment of recurrent IVL, PBML, and recurrent LPD.

METHODS

This was a pilot study to evaluate the safety and efficacy of sirolimus in the treatment of leiomyomatosis (ClinicalTrials.gov identifier NCT03500367) conducted in China. Patients received oral sirolimus 2 mg once a day for a maximum of 60 months or until disease progression, intolerable toxicity, withdrawal of consent, or investigator decision to stop. The primary end point of this study was the objective response rate. Secondary end points included safety and tolerability, disease control rate, and progression-free survival.

RESULTS

A total of 15 patients with leiomyomatosis were included in the study, including five with recurrent IVL, eight with PBML and two with recurrent LPD. The median follow-up time was 15 months (range 6-54 months), nine patients (60%) had treatment-related adverse events (including all levels), and two patients had treatment-related grade 3 or 4 adverse events. The objective response rate was 20.0% (95% CI, 7.1-45.2%), and the disease control rate was 86.7% (95% CI, 62.1-96.3%). Partial response was achieved in three patients. The median response time in the three partial response patients was 33 months (range 29-36 months), and the sustained remission time of these three patients reached 0, 18, and 25 months, respectively.

CONCLUSIONS

Sirolimus was safe and effective in the treatment of recurrent IVL, PBML, and recurrent LPD.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT03500367. Registered on 18 April 2018.

A case of massive fetal cardiac rhabdomyoma: ultrasound features and management

We report the case of a massive fetal cardiac rhabdomyoma recently occurred at our clinic. A woman at 23 weeks of gestational age was referred to our center for a fetal cardiac echogenic mass of 26 mm detected at the second-trimester screening ultrasound. During pregnancy, though, the mass progressively increased its dimensions until reaching 48 mm in diameter at 37 weeks of gestation. Fetal echoencephalography and brain magnetic resonance did not show any further fetal anomalies, but molecular genetic testing at amniocentesis revealed a heterozygotic missense variant of gene TSC2 associated with Tuberous Sclerosis. The mass was therefore most likely preferable to a single large rhabdomyoma of gradually increasing dimensions. The baby was delivered at term with a cesarean section. Because of the rhabdomyoma remarkable size and newborn ECG electrical alterations, postnatal therapies with Flecainide and Everolimus were started. Everolimus treatment led to a significant and progressive reduction in the cardiac mass volume. This case, therefore, shows the efficacy of what seems to be a promising treatment in pediatric patients with large rhabdomyomas.Learning points:Rhabdomyomas may present with different features: most often they appear as multiple masses along the interventricular sept, but they may also appear as a single large thoracic mass.When a rhabdomyoma is suspected, genetic counseling is recommended.Both before and after birth, a multidisciplinary approach is useful to choose the appropriate therapy for the newborn.mTOR inhibitors therapies look like promising therapeutic approaches to stimulate the involution of rhabdomyomas.

Effect of different dose regimens of everolimus in a series of neonates with giant cardiac rhabdomyomas

Everolimus is a mTOR inhibitor that has been increasingly used in high-risk cardiac rhabdomyomas in recent years. There are questions regarding the optimal dose and duration of therapy with everolimus for cardiac rhabdomyomas. The purpose of this study was to examine retrospectively the dosage-efficacy relationship in seven babies diagnosed with rhabdomyoma treated with different everolimus dose regimens retrospectively. Cardiac rhabdomyoma diagnosis was made in six of seven babies during the prenatal period. Indication of everolimus was an obstruction in six patients and supraventricular tachycardia which is resistant to antiarrhythmic drugs in the remaining one patient. The median age was 8 days (range; 2-105 days) at the time of starting everolimus. It was administered at a dose of 0.25 mg twice a day for two days a week in four patients; 0.1 mg/day in two and 0.4 mg/day in one patient. Serum everolimus level was kept between 5 and 15 ng/ml. All seven cases showed significant regression of cardiac rhabdomyoma within four weeks, and supraventricular tachycardia was controlled in two weeks after everolimus administration.This study demonstrates that everolimus was effective in accelerating regression of the cardiac rhabdomyoma. Dose with 2 × 0,25 mg/day, 2 days a week, seems appropriate. However, lower doses such as 0.1 mg/day are also effective. But dose adjustment should be made according to serum level monitoring.

Paradigm shift in the treatment of tuberous sclerosis: Effectiveness of everolimus

Tuberous sclerosis complex (TSC) is an autosomal dominant disease characterised by abnormal cell proliferation and differentiation that affects multiple organs and can lead to the growth of hamartomas. Tuberous sclerosis complex is caused by the disinhibition of the protein mTOR (mammalian target of rapamycin). In the past, various therapeutic approaches, even if only symptomatic, have been attempted to improve the clinical effects of this disease. While all of these therapeutic strategies are useful and are still used and indicated, they are symptomatic therapies based on the individual symptoms of the disease and therefore not fully effective in modifying long-term outcomes. A new therapeutic approach is the introduction of allosteric inhibitors of mTORC1, which allow restoration of metabolic homeostasis in mutant cells, potentially eliminating most of the clinical manifestations associated with Tuberous sclerosis complex. Everolimus, a mammalian target of the rapamycin inhibitor, is able to reduce hamartomas, correcting the specific molecular defect that causes Tuberous sclerosis complex. In this review, we report the findings from the literature on the use of everolimus as an effective and safe drug in the treatment of TSC manifestations affecting various organs, from the central nervous system to the heart.

Cardiac Masses Discovered by Echocardiogram; What to Do Next?

Cardiac tumors are rare conditions, typically diagnosed on autopsy, but with the advancement of imaging techniques they are now encountered more frequently in clinical practice. Echocardiography is often the initial method of investigation for cardiac masses and provides a quick and valuable springboard for their characterization. While some cardiac masses can be readily identified by echocardiography alone, several require incorporation of multiple data points to reach diagnostic certainty. Herein, we will provide an overview of the main clinical, diagnostic, and therapeutic characteristics of cardiac masses within the framework of their location.

Effect of mTOR Inhibitors in Epilepsy Treatment in Children with Tuberous Sclerosis Complex Under 2 Years of Age

INTRODUCTION

Mechanistic target of rapamycin (mTOR) inhibitors sirolimus and everolimus are an effective therapy for subependymal giant cell astrocytomas, cardiac rhabdomyomas, renal angiomyolipomas, and lymphangioleiomyomatosis associated with tuberous sclerosis complex (TSC). Everolimus was recently approved in the EU and the USA for the treatment of refractory focal-onset seizures. Despite frequent use of mTOR inhibitors, there are only a few studies on their effect on epilepsy control in children under 2 years of age. This study aims to assess the effect of adjunctive mTOR inhibitor treatment on seizure frequency in this age group.

METHODS

We performed retrospective data analysis of medical records of patients with TSC who initiated sirolimus or everolimus under the age of 2 years. Participants' antiseizure medication was adjusted according to their epilepsy control independently from mTOR inhibitor administration. The data was assessed separately for patients treated with mTOR inhibitors before and after the onset of seizures. We also compared the treatment group with a matched control group. The follow-up duration was up to 24 months.

RESULTS

Twenty-one patients with TSC from two clinical centers were included in the study. Nine participants had no history of seizures before mTOR inhibitor initiation. Twelve reported active epilepsy in the month prior to treatment initiation. Most patients treated preventively with mTOR inhibitors did not report active epilepsy at the end of their follow-up. In the second group, the mean frequency of seizures decreased with time. According to the comparative analysis, seizure control was better in the groups treated with mTOR inhibitors.

CONCLUSION

Patients with TSC treated with mTOR inhibitors demonstrated better seizure control than individuals without this treatment. Adjunctive pharmacotherapy with mTOR inhibitors appears to have a beneficial effect on epilepsy outcome in young children. Further prospective clinical trials should be conducted to determine the efficacy of mTOR inhibitors on epilepsy in patients with TSC under the age of 2 years.

Kinase Inhibitors in Genetic Diseases

Over the years, several studies have shown that kinase-regulated signaling pathways are involved in the development of rare genetic diseases. The study of the mechanisms underlying the onset of these diseases has opened a possible way for the development of targeted therapies using particular kinase inhibitors. Some of these are currently used to treat other diseases, such as cancer. This review aims to describe the possibilities of using kinase inhibitors in genetic pathologies such as tuberous sclerosis, RASopathies, and ciliopathies, describing the various pathways involved and the possible targets already identified or currently under study.

Imaging Recommendations for Diagnosis, Staging, and Management of Hereditary Malignancies

Hereditary cancer syndromes, characterized by genetically distinct neoplasms developing in specific organs in more than one family members, predispose an individual to early onset of distinct site-specific tumors. Early age of onset, multiorgan involvement, multiple and bilateral tumors, advanced disease at presentation, and aggressive tumor histology are few characteristic features of hereditary cancer syndromes. A multidisciplinary approach to hereditary cancers has led to a paradigm shift in the field of preventive oncology and precision medicine. Imaging plays a pivotal role in the screening, testing, and follow-up of individuals and their first- and second-degree relatives with hereditary cancers. In fact, a radiologist is often the first to apprise the clinician about the possibility of an underlying hereditary cancer syndrome based on pathognomonic imaging findings. This article focuses on the imaging spectrum of few common hereditary cancer syndromes with specific mention of the imaging features of associated common and uncommon tumors in each syndrome. The screening and surveillance recommendations for each condition with specific management approaches, in contrast to sporadic cases, have also been described.

Safety of Sirolimus in Patients with Tuberous Sclerosis Complex under Two Years of Age-A Bicenter Retrospective Study

BACKGROUND

mTOR inhibitors are a novel pharmacotherapy recommended for subependymal giant astrocytomas, refractory epilepsy, and the treatment of the other clinical manifestations of tuberous sclerosis complex (TSC). Clinical trials on everolimus proved it to be effective and safe in children. Despite its common use in clinical practice, the research on sirolimus is limited. This study is the first to determine and assess the severity of the adverse effects (AEs) of sirolimus administered to children with TSC under two years of age.

METHODS

We performed a bicenter retrospective data analysis of medical records of individuals with TSC who initiated therapy with sirolimus under the age of two.

RESULTS

Twenty-one patients were included in the study. At least one AE was reported in all participants. The most prevalent AEs were anemia, thrombocytosis, and hyperlipidemia. Infections and mouth ulcerations, often reported in the studies on older patients, were infrequent and of mild or moderate grade.

CONCLUSIONS

Adverse effects associated with sirolimus use in infants and young children with TSC are frequent yet not life- or health-threatening. Further multicenter prospective clinical trials should determine the long-term safety of sirolimus.

Case report: Accelerated regression of giant cardiac rhabdomyomas in neonates with low dose everolimus

Cardiac rhabdomyoma (CRHM) is the principal cardiac tumor in children and is most often associated with tuberous sclerosis complex (TSC). Mutations in the TSC1 and TSC2 genes cause the overactivation of the mammalian Target of Rapamycin (mTOR). This protein family is responsible for abnormal cell proliferation leading to the formation of CRHMs and hamartomas in other organs. Despite the tendency for spontaneous regression, some CRHMs can cause heart failure and intractable arrhythmias, requiring surgical resection. In recent years, the use of everolimus and sirolimus (mTOR inhibitors) in the treatment of CRHMs has been reported. We report two cases of neonates with giant rhabdomyomas, with hemodynamic repercussions treated with low-dose everolimus (4.5 mg/m²/week). In both cases, we obtained an approximate decrease of 50% in the total area of the mass after three weeks of treatment. Despite rebound growth after stopping the drug, we were able to evidence that the use of low doses of everolimus immediately after birth is effective and safe in the treatment of giant CRHMs, avoiding surgical resection of the tumor and associated morbidity and mortality.

Vigabatrin-associated brain abnormalities on MRI in tuberous sclerosis complex patients with infantile spasms: are they preventable?

Background

Vigabatrin (VGB) is currently the most widely prescribed first-line medication for individuals with infantile spasms (IS) and especially for those with tuberous sclerosis complex (TSC), with demonstrated efficacy. Meanwhile, its adverse events, such as vigabatrin-associated brain abnormalities on magnetic resonance imaging (MRI; VABAM), have also been widely reported.

Objectives

The objectives of this study were to observe the occurrences of VABAM in patients with IS caused by TSC (IST) and further explore the associated risk factors.

Methods

Children with IS receiving VGB were recruited from our institution; clinical, imaging, and medication data were collected. Cerebral MRI was reviewed to determine the occurrence of VABAM. Group comparisons (IS caused by TSC and other etiologies) were performed; subgroup analyses on IST were also performed. Next, a retrospective cohort study of children taking VGB was conducted to explore risk/protective factors associated with VABAM.

Results

The study enrolled 172 children with IS who received VGB. VABAM was observed in 38 patients (22.1%) with a peak dosage of 103.5 ± 26.7 mg/kg/day. Subsequent analysis found the incidence of VABAM was significantly lower in the 80 patients with IST than in the 92 patients with IS caused by other etiologies (10% versus 32.6%, p-value < 0.001). In subgroup analyses within the IST cohort, VABAM was significantly lower in children who received concomitant rapamycin therapy. Univariate and multivariate logistic regression analysis of the 172 IS children showed that treatment with rapamycin was the independent factor associated with a lower risk of VABAM; similar results were observed in the survival analysis.

Conclusion

The incidence of VABAM was significantly lower in IST patients. Further research is needed to examine the mechanisms that underlie this phenomenon and to determine if treatment with rapamycin may reduce the risk of VABAM.

Tuberous sclerosis complex and epilepsy in infancy: prevention and early diagnosis

Numerous studies showed that epilepsy represents a high burden in Tuberous Sclerosis Complex (TSC), affecting 63 to 78% of the patients. Epilepsy will be refractory to medication in over 60% of cases in early presentations, and accompanied by intellectual disabilities and/or autism spectrum disorders. The emerging experimental and clinical data suggest that the molecular and cellular changes triggered by seizures, particularly during the first weeks of life, can be limited by early action. Making any effort to avoid or delay epilepsy onset is a promising pathway to improve global outcome for TSC patients, although it is not possible to tidy up the specific roles of seizures, interictal abnormalities, and cortical abnormalities upon neurodevelopment. Early diagnosis of epilepsy can be made during a "symptomatic phase," shortly after the onset of seizures (focal seizures or spasms), revealing the TSC in a young infant. As soon as the diagnosis is made, a treatment with Vigabatrin is now recommended. The diagnosis of epilepsy can also be performed during a "presymptomatic phase", with the improvement of fetal and neonatal diagnosis of TSC. Recent studies demonstrated a significant delay of more than 3 months between the detection of EEG abnormalities and the first clinical seizures, which allows to consider a preventive treatment. Beside vigabatrin, mTOR inhibitors may have a place in this early management. The last recommendations about early detection and treatment of epilepsy in TSC will be detailed in this review. © 2022 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Differential diagnosis of cardiac tumors: General consideration and echocardiographic approach

Cardiac tumors may be primary (either benign or malignant) or secondary (malignant) and are first detected by echocardiography in most cases. The cardiologist often challenges their identification, the differential diagnosis and the best therapeutic approach. Malignant tumors have usually a poor prognosis, which may be significantly improved by appropriate and timely therapies. The echocardiographic aspects of benign and malignant cardiac tumors described in this article, along with a clinical evaluation may orient the differential diagnosis and aid in choosing the further steps useful to define the nature of the mass.

Characterization and management of facial angiofibroma related to tuberous sclerosis complex in the United States: retrospective analysis of the natural history database

Background

Facial angiofibroma is the most predominant cutaneous manifestation of tuberous sclerosis complex (TSC), a rare autosomal dominant genetic disorder impacting the mechanistic target of rapamycin (mTOR). Facial angiofibroma can bleed spontaneously, impair eyesight, and cause aesthetic disfiguration causing psychological and social stress. To date, there is little or no evidence on the demographics, and other TSC features associated with facial angiofibroma or the use of mTOR inhibitor for the management of facial angiofibroma. This is a retrospective study of TSC Alliance’s Natural History Database aimed to characterize facial angiofibroma and to evaluate features associated with a higher risk of facial angiofibroma or the use of topical mTOR inhibitors for the management of facial angiofibroma. Data in the NHD was obtained from 18 clinical sites in the US since 2006.

Results

Of the 2240 patients, 2088 patients were enrolled in the US and data from 2057 patients were included in this analysis. The mean (median) age of overall TSC patients was 22.4 (19.0) years. A total of 69 patients were ≤ 5 years of age. Facial angiofibroma was noted in 1329 (64.6%) patients with TSC. Patients with facial angiofibroma were older on average (Mean: 25.9 [median, 23.0] vs. 16.0 [12.4 years] years, p < 0.0001). In patients with vs. without facial angiofibroma, TSC2 mutation (38.9% vs. 34.8%) was more common than TSC1 mutation (12.3% vs. 18.1%), and the incidence rate of most of the other TSC-related manifestations was significantly higher in patients with facial angiofibroma. Majority of patients had focal seizures (72.8% vs. 60.7%), followed by angiomyolipoma (63.7% vs. 21.8%) and renal cysts (59.4% vs. 33.5%). The age groups, 11–17 (odds ratio [OR], 2.53) and 18–45 years (5.98), TSC2 mutation (1.31), focal seizures (1.50), ADHD (1.47) angiomyolipoma (2.79), and renal cysts (2.63) were significantly associated with a higher risk of facial angiofibroma based on multivariate logistic regression. Abrasive or laser therapy was used by 17.1% and 2.6% patients, respectively. Topical mTOR inhibitor use was noted for 329 (24.8%) patients with facial angiofibroma. Overall systemic mTOR inhibitor use was observed in 399 (30.0%) patients for management of one or more TSC manifestations. Use of systemic mTOR inhibitor for facial angiofibroma was noted for 163 (12.3%) patients, among whom only 9 (0.7%) patients used exclusively for the management of facial angiofibroma. Of the patients with facial angiofibroma, 44.6% did not receive any treatment. Significantly higher use of topical mTOR inhibitor was associated with the 11–17 years age group (OR, 1.67), anxiety (1.57), angiomyolipoma (1.51), and renal cysts (1.33).

Conclusions

The presence of TSC2 mutations and most other TSC-related manifestations was significantly higher in patients with facial angiofibroma. About one-fourth of patients with facial angiofibroma used a topical mTOR inhibitor and use of systemic mTOR inhibitor for the management of facial angiofibroma or for the other manifestations was noted for 30.0%. About 44.6% of patients did not receive any treatment for the management of facial angiofibroma.

Tuberous sclerosis complex with skin lesions as the initial presentation: A case report and multidisciplinary discussion

We reported a case of tuberous sclerosis complex with facial angiofibroma as the initial presentation and conducted a multidisciplinary discussion. The patient, a young female, was admitted to the Department of Dermatology for cosmetic purpose. After the examination, she was found to have multiple system involvement, including a large renal angiomyolipoma pressing on the liver. She never had any subjective symptom. After consultation by the multidisciplinary team of tuberous sclerosis complex, the patient was treated with everolimus orally and followed up regularly. It is suggested that dermatologists should pay attention to the systemic involvement of patients with tuberous sclerosis complex. Early intervention can prolong the life of patients and improve their life quality. Multidisciplinary collaboration for lifelong disease management is the key to enhance the diagnosis and treatment for tuberous sclerosis complex and enhance the prognosis of patients.

Monitoring and Managing Patients with Tuberous Sclerosis Complex: Current State of Knowledge

Tuberous sclerosis complex (TSC) is a rare genetic disease of autosomal dominant transmission that, in most cases, results from the presence of pathogenic variants of the TSC1 or TSC2 genes, encoding hamartin and tuberin, respectively. It is a multisystemic disease, affecting most frequently the brain, skin, kidney, and heart. The wide variety of possible clinical manifestations, given this multisystem dimension, makes the follow-up of patients with TSC an exercise of multidisciplinarity. In fact, these patients may require the intervention of various medical specialties, which thus have to combine their efforts to practice a medicine that is truly holistic. The past few years have witnessed a dramatic leap not only in the diagnosis and management of TSC patients, with standard monitoring recommendations, but also in the therapeutic field, with the use of mTORC1 inhibitors. In this article, we review the clinical manifestations associated with TSC, as well as the treatment and follow-up strategies that should be implemented, from a multidisciplinary perspective.

Perfect match: mTOR inhibitors and tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that presents with diverse and complex clinical features and involves multiple human systems. TSC-related neurological abnormalities and organ dysfunction greatly affect the quality of life and can even result in death in patients with TSC. It is widely accepted that most TSC-related clinical manifestations are associated with hyperactivation of the mammalian target of rapamycin (mTOR) pathway caused by loss‑of‑function mutations in TSC1 or TSC2. Remarkable progress in basic and translational research has led to encouraging clinical advances. Although mTOR inhibitors (rapamycin/everolimus) demonstrate great potential in TSC management, two major concerns hamper their generalized application. One is the frequent manifestation of adverse events, such as stomatitis, infections, and menstrual disorders; and the other is the poor response in certain patients. Thus, indicators are required to effectively predict the efficacy of mTOR inhibitors. Herein, we have summarized the current utilization of mTOR inhibitors in the treatment of TSC and focused on their efficacy and safety, in an attempt to provide a reference to guide the treatment of TSC.

Hyperactivation of mammalian target of rapamycin (mTOR) is essential in the pathogenesis of tuberous sclerosis complex (TSC) and can serve as a therapeutic target.

mTOR inhibitors have shown considerable success in multiple clinical trials for the treatment of TSC, including neurological, pulmonary, cardiac, renal, and cutaneous phenotypes.

mTOR inhibitors are associated with adverse events, which should be considered during the management of TSC.

Indicators to predict mTOR inhibitor efficacy are required to select patients who are likely to benefit from such therapy.