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.

Prenatal Sirolimus Treatment for Rhabdomyomas in Tuberous Sclerosis

BACKGROUND

In tuberous sclerosis, most cardiac rhabdomyomas regress spontaneously. In some cases, the tumors can cause life-threatening hemodynamic compromise requiring subsequent surgical resection. The mechanistic target of rapamycin inhibitors everolimus and sirolimus have shown to be effective treatments for multiple conditions. There are four reports of off-label treatment with transplacental sirolimus for fetal rhabdomyomas due to tuberous sclerosis complex. The optimal dosing regimen is unknown.

METHODS

We reviewed the medical records of all patients treated prenatally with sirolimus for rhabdomyomas. All fetuses had a clinical and molecular diagnosis of tuberous sclerosis complex (2012 Consensus Diagnostic Criteria, including a positive genetic test). Clinical history, mechanistic target of rapamycin inhibitor dosing and levels, outcome, and adverse events were reviewed after initiation of sirolimus treatment.

RESULTS

Three fetuses were treated with maternal sirolimus. Dosing regimens and subsequent trough levels differed from 1 mg/day to 6 mg/day and <1.0 ng/mL to 12.2 ng/mL. Cardiac rhabdomyomas gradually shrank in all patients. Growth restriction was noted in one patient. No severe adverse events occurred during the treatment period.

CONCLUSIONS

Maternal sirolimus appears to be a safe treatment option in prenatally detected rhabdomyomas with possible need for intervention. Follow-up visits with fetal ultrasound, echocardiography, and laboratory work should be performed weekly during the treatment period. The optimal dosing and trough level timepoints remain unclear. Based on our results, we recommend a sirolimus starting dose of at least 2 mg/m²/day, preferably 3-3.5 mg/m²/day to achieve a target trough level of 10-12 ng/mL.

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.