TSC2/PKD1 contiguous deletion syndrome in a pregnant woman: A case report

TSC2/PKD1 contiguous gene deletion syndrome is a disease caused by the deletions of the TSC2 and PKD1 genes. This is a rare contiguous genomic disease with clinical manifestations of tuberous sclerosis and polycystic kidney disease. To our knowledge, this case report is the first known case of TSC2/PKD1 contiguous gene deletions in a pregnant woman. The patient had multiple renal cysts, angiomyolipoma, hypomelanotic macules, shagreen patch, subependymal giant cell astrocytoma, multiple cortical tubers, and subependymal nodules. The patient underwent genetic testing. To exclude genetic defects in the fetus, prenatal fetal genetic testing was performed after obtaining the patient's consent. We found an increasing trend in the size of renal cysts and renal angiomyolipomas in patients with polycystic kidney with tuberous sclerosis during pregnancy. Through enhanced clinical monitoring of patients and prenatal genetic testing of the fetus, timely and effective clinical intervention for the mother may be achieved, thus obtaining the best possible outcome for both mother and fetus.

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.

Clinical profile of tuberous sclerosis complex patients with and without epilepsy: a need for awareness for early diagnosis

BACKGROUND

Tuberous sclerosis complex (TSC) is a multisystemic disorder. Its clinical features manifest differently in several organs, prompting the need for better knowledge.

OBJECTIVE

The goal of the present study is to evaluate the neurological findings of TSC, such as cerebral lesions and epilepsy, and to raise awareness of non-neurological findings that could contribute to an earlier diagnosis and treatment.

METHODS

This was a natural history study of patients with a definitive diagnosis of TSC who were referred to a specialized outpatient clinic and followed-up for 2 years with clinical and radiological exams.

RESULTS

A total of 130 TSC patients (59 males [45.4%], mean age 20.4 years old [1 to 56 years old]); 107 patients (82.3%) were diagnosed with epilepsy. Seizures predominantly began at < 1 year old (72.8%); focal seizures predominated (86.9%); epileptic spasms occurred in 34.5% of patients, and refractory epilepsy was present in 55.1%. Neuropsychiatric disorders, cortical tubers and cerebellar tubers were significantly more frequent in the epilepsy group. Moreover, rhabdomyomas were significantly more frequent in the epilepsy group (p = 0.044), while lymphangioleiomyomatosis was significantly less frequent in the epilepsy group (p = 0.009). Other non-neurological findings did not differ significantly between the groups with and without epilepsy.

CONCLUSIONS

The present study of TSC patients demonstrated the predominantly neurological involvement and significantly higher proportion of TSC-associated neuropsychiatric disorders in the epilepsy group. Higher proportions of cortical and cerebellar tubers may be a risk factor for epilepsy and neurodevelopmental disorders.

Periodontoid Pseudotumor in Tuberous Sclerosis Associated With Neck Diffuse Lipomatosis

Tuberous sclerosis (TS) is a genetic multisystem disorder associated with the development of benign tumors in many organs. Diffuse lipomatosis, which represents the overgrowth of fatty tissue in one part of the body, is a very rare finding reported in patients with tuberous sclerosis. We describe the case of a patient with diffuse lipomatosis in the right scapular, posterior cervical and perivertebral regions, associated with a space-occupying lesion adjacent to the odontoid process of C2 that appeared to be a pseudotumor, and discuss possible relation between these entities.

Shared mechanisms of neural circuit disruption in tuberous sclerosis across lifespan: Bridging neurodevelopmental and neurodegenerative pathology

Tuberous Sclerosis (TS) is a rare genetic disorder manifesting with multiple benign tumors impacting the function of vital organs. In TS patients, dominant negative mutations in TSC1 or TSC2 increase mTORC1 activity. Increased mTORC1 activity drives tumor formation, but also severely impacts central nervous system function, resulting in infantile seizures, intractable epilepsy, and TS-associated neuropsychiatric disorders, including autism, attention deficits, intellectual disability, and mood disorders. More recently, TS has also been linked with frontotemporal dementia. In addition to TS, accumulating evidence implicates increased mTORC1 activity in the pathology of other neurodevelopmental and neurodegenerative disorders. Thus, TS provides a unique disease model to address whether developmental neural circuit abnormalities promote age-related neurodegeneration, while also providing insight into the therapeutic potential of mTORC1 inhibitors for both developing and degenerating neural circuits. In the following review, we explore the ability of both mouse and human brain organoid models to capture TS pathology, elucidate disease mechanisms, and shed light on how neurodevelopmental alterations may later contribute to age-related neurodegeneration.

MicroRNA Expression Profile in TSC Cell Lines and the Impact of mTOR Inhibitor

The aim of this study was to assess the potential implication of microRNA on tuberous sclerosis (TSC) pathogenesis by performing microRNA profiling on cell lines silencing TSC1 or TSC2 genes using qPCR panels, before and after incubation with rapamycin. Significant differences in expression were observed between samples before and after rapamycin treatment in nineteen miRNAs in TSC1, five miRNAs in TSC2 and seven miRNAs in controls. Of miRNAs dysregulated before rapamycin treatment, three normalized after treatment in the TSC1 group (miR-21-3p, miR-433-3p, let-7g-3p) and one normalized in the TSC2 group (miR-1224-3p). Of the miRNAs dysregulated before rapamycin treatment in the TSC1 and TSC2 groups, two did not normalize after treatment (miR-33a-3p, miR-29a-3p). The results of the possible targets indicated that there are four common genes with seed regions susceptible to regulation by those miRNAs: ZBTB20, PHACTR2, PLXNC1 and ATP1B4. Our data show no changes in mRNA expression of these targets after rapamycin treatment. In conclusion, results of our study indicate the involvement of miRNA dysregulation in the pathogenesis of TSC. Some of the miRNA might be used as markers of treatment efficacy and autonomic miRNA as a target for future therapy.

Management of Renal Angiomyolipomas in Tuberous Sclerosis Complex: A Case Report and Literature Review

We report a case of misdiagnosed tuberous sclerosis complex (TSC) in a patient without TSC gene variant presenting with bilateral renal angiomyolipomas and seizures in the context of strong family history of polycystic kidney disease. Clinical diagnosis of tuberous sclerosis complex was made and treatment with everolimus reduced size of renal angiomyolipomas. In this case, report we discuss the association between tuberous sclerosis complex and polycystic kidney disease and novel treatment for TSC.

Case report: A hybrid technique for a safe nephrectomy in a giant kidney angiomyolipoma

Background

Giant angiomyolipoma is usually associated with genetic syndromes and complications (spontaneous rupture and bleeding, hematuria, hypertension) and mass-related symptoms (flank and abdominal pain).

Case presentation

We present a case of a 20-year-old woman suffering from tuberous sclerosis who was referred to our hospital with a giant angiomyolipoma causing abdominal pain. A contrast-enhanced computed tomography showed a left angiomyolipoma, measuring 28 cm × 17 cm × 27 cm. After a multidisciplinary team discussion, the patient was submitted for a nephrectomy. Percutaneous temporary occlusion of the main renal artery was achieved through an endovascular balloon catheter. Through the balloon catheter guidewire, 2,500 IU of heparin was infused to reduce the risk of tumor vein thrombosis and venous embolism. This allowed a safe kidney manipulation through a left thoracoabdominal approach. The postoperative course was uneventful. Pathology showed a 40 cm × 30 cm × 9 cm and 10 kg AML. One year after surgery, the patient is on follow-up, and her estimated glomerular filtration is 120.5 ml/min/1.73 m².

Conclusion

The present case showed that the endovascular control of the main renal artery could be considered a useful approach to safely managing huge renal masses when renal hilar control is expected to be very difficult.

[Tuberous sclerosis complex: diagnosis and current treatment]

Tuberous sclerosis complex is an autosomal dominant genetic multisystemic disorder caused primarily by mutations in one of the two tumor suppressor genes TSC1 or TSC2, resulting in increased activation of the mTOR pathway. Regarding clinical manifestations, a wide range of phenotypic variability exists, with symptoms constellations that may differ in affected organs (brain, skin, heart, eyes, kidneys, lungs), age of presentation and severity, but usually with great impact in biopsychosocial aspects of health and in quality of life. Main clinical neurological features are epilepsy (frequently, antiepileptic drug-resistant epilepsy), neuropsychiatric disorders, and subependymal giant cell astrocytomas. Recently, many therapeutic strategies have developed, including preventive treatment of epilepsy, new options for treatment of epilepsy as cannabidiol, mTOR inhibitors, ketogenic diet, and a more precise epilepsy surgery. Subependymal giant cell astrocytomas may require surgical procedures or mTOR inhibitors treatment. mTOR inhibitors may also be useful for other comorbidities. To improve quality of life of patients with tuberous sclerosis complex, it is essential to be able to deliver an integrated approach by specialized multidisciplinary teams, coordinated with primary care physicians and health professionals, that include access to treatments, attention of psychosocial aspects, and an adequate health care transition from pediatric to adult care.

Population Pharmacokinetic Analysis and Dosing Optimization of Sirolimus in Children With Tuberous Sclerosis Complex

Sirolimus is confirmed to be effective in the treatment of tuberous sclerosis complex (TSC) and related disorders. The study aims to establish a population pharmacokinetic model of oral sirolimus for children with TSC and provide an evidence-based approach for individualization of sirolimus dosing in the pediatric population. A total of 64 children were recruited in this multicenter, retrospective pharmacokinetic study. Whole-blood concentrations of sirolimus, demographic, and clinical information were collected and analyzed using a nonlinear mixed-effects population modeling method. The final model was internally and externally validated. Then Monte Carlo simulations were performed to evaluate and optimize the dosing regimens. In addition, the efficacy and safety of sirolimus therapy was assessed retrospectively in patients with epilepsy or cardiac rhabdomyomas associated with TSC. Finally, the sirolimus pharmacokinetic profile was described by a 1-compartment model with first-order absorption and elimination along with body weight and total daily dose as significant covariates. The typical population parameter estimates of apparent volume of distribution and apparent clearance were 69.48 L and 2.79 L/h, respectively. Simulations demonstrated that dosage regimens stratified by body surface area may be more appropriate for children with TSC. These findings could be used to inform individualized dosing strategies of sirolimus for pediatric patients with TSC.

Case report: The origin of transmantle-like features

The transmantle sign is considered to be a magnetic resonance imaging feature specific to patients with type II focal cortical dysplasia; however, this sign can be difficult to distinguish from other pathologies, such as a radial-oriented white matter band in tuberous sclerosis. Here, we report a case showing a high-intensity area on T2-weighted and fluid-attenuated inversion recovery images extending from the ventricle to the cortex associated with atypical histopathological findings containing corpora amylacea. This case demonstrates that some instances of transmantle signs may be due to corpora amylacea accumulation.

Confirmation of Decreased Rates of Cerebral Protein Synthesis In Vivo in a Mouse Model of Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that results in intellectual disability and, in ∼50% of patients, autism spectrum disorder. The protein products that are altered in TSC (TSC1 and TSC2) form a complex to inhibit the mammalian target of rapamycin [mTOR; mTOR complex 1 (mTORC1)] pathway. This pathway has been shown to affect the process of mRNA translation through its action on ribosomal protein S6 and 4-elongation binding protein 1. It is thought that mutations in the TSC proteins lead to upregulation of the mTORC1 pathway and consequently an increase in protein synthesis. Unexpectedly, our previous study of a mouse model of TSC (Tsc2Djk +/) demonstrated decreased in vivo rates of protein synthesis throughout the brain. In the present study, we confirm those results in another Tsc2+/- mouse model, one with a different mutation locus and on a mixed background (Tsc2Mjg +/-). We also examine mTORC1 signaling and possible effects of prior isoflurane anesthesia. Because measurements of protein synthesis rates in vivo require surgical preparation of the animal and anesthesia, we examine mTORC1 signaling pathways both under baseline conditions and following recovery from anesthesia. Our results demonstrate regionally selective effects of prior anesthesia. Overall, our results in both in vivo models suggest differences to the central hypothesis regarding TSC and show the importance of studying protein synthesis in vivo Significance StatementProtein synthesis is an important process for brain function. In the disorder, tuberous sclerosis complex (TSC), the inhibition of the mammalian target of rapamycin (mTOR) pathway is reduced and this is thought to lead to excessive protein synthesis. Most studies of protein synthesis in models of TSC have been conducted in vitro We report here confirmation of our previous in vivo study showing decreased brain protein synthesis rates in a second mouse model of TSC, results counter to the central hypothesis regarding TSC. We also explore the possible influence of prior isoflurane exposure on signaling pathways involved in regulation of protein synthesis. This study highlights a novel aspect of TSC and the importance of studying cellular processes in vivo.

mTOR Inhibitor Treatment in Patients with Tuberous Sclerosis Complex Is Associated with Specific Changes in microRNA Serum Profile

The aim of this study was to determine the serum profiles of miRNAs in patients with tuberous sclerosis (TSC) upon sirolimus treatment and compare them with those previously treated with everolimus in a similarly designed experiment. Serum microRNA profiling was performed in ten TSC patients before sirolimus therapy and again after 3–6 months using qPCR panels (Exiqon). Of 752 tested miRNAs, 28 showed significant differences in expression between TSC patients before and after sirolimus treatment. Of these, 11 miRNAs were dysregulated in the same directions as in the sirolimus groupcompared with the previously described everolimus group, miR-142-3p, miR-29c-3p, miR-150-5p, miR-425-5p, miR-376a-3p, miR-376a-3p, miR-532-3p, and miR-136-5p were upregulated, while miR-15b-3p, miR-100-5p, and miR-185-5p were downregulated. The most significant changes of expression, with fold changes exceeding 1.25 for both treatments, were noted for miR-136-5p, miR-376a-3p, and miR-150-5p. The results of a pathway analysis of the possible target genes for these miRNAs indicated the involvement of the Ras and MAPK signaling pathway. Upregulation of miR-136, miR-376a-3p, and miR-150-5p was noted in TSC patients treated with mTOR inhibitors, indicating a role in the downregulation of the mTOR pathway. Further studies are needed to determine the relationship between upregulated microRNAs and treatment efficacy.

Noninvasive prenatal diagnosis based on cell-free DNA for tuberous sclerosis: A pilot study

BACKGROUND

Noninvasive prenatal diagnosis (NIPD) based on cell-free DNA (cfDNA) has been introduced into the clinical application for some monogenic disorders but not for tuberous sclerosis (TSC) yet, which is an autosomal dominant disease caused by various variations in TSC1 or TSC2 gene. We aimed to explore the feasibility of NIPD on TSC.

METHODS

We recruited singleton pregnancies at risk of TSC from 14 families with a proband child. Definitive NIPD for TSC was performed using targeted next-generation sequencing of cfDNA in parallel with maternal white blood cell DNA (wbcDNA). The NIPD results were validated by amniocentesis or postnatal gene testing and follow-up of the born children.

RESULTS

Missense mutations, nonsense mutations, frameshift mutations, and splice-site variants which were obtained through de-novo, maternal, or paternal inheritance were included. The mean and minimum gestational weeks of NIPD were 17.18 ± 5.83 and 8 weeks, respectively. The NIPD results were 100% consistent with the amniocentesis or postnatal gene testing and follow-up of the born children.

CONCLUSION

This study demonstrates that NIPD based on cfDNA is feasible for TSC, but required to be confirmed with more samples. Studies on TSC can contribute to the application and promotion of NIPD for monogenic disorders.

Complex Arterial Pathology of Angiomyolipomas of Tuberous Sclerosis

Based on observations at angiography, it was hypothesized that angiomyolipomas (AMLs) associated with tuberous sclerosis complex (TSC) have a more robust parasitic blood supply and require more complex embolization involving lower order vessels compared with the non-TSC patients' AMLs. This was a retrospective review of 71 patients who underwent angiography and embolization for renal AML at multiple centers within a single health system. All of the patients with TSC (11/11) were found to have "complex" tumor vascular supply. Of the patients with sporadic AML, 51/60 (85%) had "simple" tumor vascular supply. Sporadic cases with a complex tumor blood supply were larger tumors, with an average size of 11.5 cm. This study supports our hypothesis that AMLs associated with TSC have more complex tumor vascularity compared with sporadic lesions, and aims to better prepare interventionalists to deal with the complex cases.

Health-related out-of-pocket expenses for children living with rare diseases - tuberous sclerosis and mitochondrial disorders: A prospective pilot study in Australian families

AIM

We aimed to describe health-related out-of-pocket (OOP) expenses incurred by Australian families living with children with chronic and complex diseases.

METHODS

A prospective pilot study of OOP expenses in families with children with tuberous sclerosis (TS) or mitochondrial disorders (MD) in 2016-2017. An initial survey assessed the family's financial situation, child's health functioning and estimated previous 6 months' and lifetime OOP expenses. Thereafter, families completed a survey each month for 6 months, prospectively tracking OOP expenses.

RESULTS

Initial surveys were completed by 13 families with 15 children; median age 7 years (range: 1-12); 5 with MD, 10 with TS. All families reported OOP expenses: 38% paid $2000 per annum, more than double the annual per-capita OOP costs reported for Australia by the Organisation for Economic Co-operation and Development. Eight families estimated $5000-$25 000 in OOP expenses over their child's lifetime and 62% of mothers reduced or stopped work due to caring responsibilities. Eleven families paid annual private health insurance premiums of $2000-$5122, but 72% said this was poor value-for-money. Prospective tracking by eight families (9 children) identified the median OOP expenditure was $863 (range $55-$1398) per family for 6 months. OOP spending was associated with visits to allied health professionals, non-prescription medicines, special foods, supplements and disposable items. Eight families paid for 91 prescription medications over 6 months.

CONCLUSION

All families caring for children with TS or MD reported OOP expenses. A larger study is needed to explore the affordability of health care for children living with a broader range of chronic diseases.

A Critical Period for Development of Cerebellar-Mediated Autism-Relevant Social Behavior

The cerebellum has been increasingly implicated in autism spectrum disorder (ASD) with many ASD-linked genes impacting both cerebellar function and development. However, the precise timing and critical periods of when abnormal cerebellar neurodevelopment contributes to ASD-relevant behaviors remains poorly understood. In this study, we identify a critical period for the development of ASD-relevant behaviors in a cerebellar male mouse model of tuberous sclerosis complex (TSC), by using the mechanistic target of rapamycin (mTOR) inhibitor, rapamycin, to pharmacologically inhibit dysregulated downstream signaling. We find independent critical periods during which abnormal ASD-relevant behaviors develop for the two core ASD diagnostic criteria, social impairments and behavioral flexibility, and delineate an anatomic, physiological, and behavioral framework. These findings not only further our understanding of the genetic mechanisms underlying the timing of ASD-relevant behaviors but also have the capacity to inform potential therapies to optimize treatment interventions.SIGNIFICANCE STATEMENT No targeted treatments currently exist for autism spectrum disorder (ASD). This complex developmental disorder has established links to genetic and circuit aberrations, yet the precise timing and coordination of these underlying mechanisms that contribute to the spectrum of physiological and behavioral abnormalities remains unclear. Cerebellar pathology is consistently seen in ASD individuals; therefore, we sought to identify the specific windows for cerebellar involvement in the development of ASD-relevant behaviors. Using pharmacologic treatment paradigms, we outline distinct critical periods of developmental vulnerability for ASD-relevant social and inflexible behaviors. From this study, we posit a refined window of time during which ASD symptoms develop that will inform therapeutic timing.

Use of cannabidiol in the treatment of epilepsy

INTRODUCTION

Cannabis sativa has been cultivated for human use for about 5,000 years, and has likewise been used in the treatment of epilepsy for thousands of years.

STATE OF THE ART

Cannabidiol (CBD), which was isolated from cannabis sativa in 1940, has an anti-seizure effect and no psychoactive activity. Its effectiveness in reducing various types of seizures has been proven in animal seizure and epilepsy models. Recent randomised, placebo-controlled trials have confirmed its effectiveness in patients with drug-resistant epilepsy.

CLINICAL IMPLICATIONS

The aim of this position paper was to present the specific mechanism of CBD's anti-seizure action and current indications for CBD's use in epilepsy. The only cannabis-derived drug that has successfully passed clinical trials and has obtained United States Food and Drug Administration and European Medicines Agency approval for epilepsy is Epidiolex®. This paper presents the outcomes of the completed clinical trials with the use of this drug.

FUTURE DIRECTIONS

CBD may be an effective drug in drug-resistant epilepsy, particularly in Dravet Syndrome, Lennox- Gastaut Syndrome and seizures associated with tuberous sclerosis complex. Additional randomised, placebo-controlled studies with CBD are needed.

Identification of a Novel Canonical Splice Site Variant TSC2 c.2967-1G>T That is Not Associated With Tuberous Sclerosis Pathogenesis

Tuberous sclerosis, also known as tuberous sclerosis complex (TSC), is an autosomal dominant defect characterized by hamartomas in multiple organ systems. Inactivating variants cause this defect in either the TSC1 gene or the TSC2 gene, leading to hamartin or tuberin protein dysfunction, thus resulting in TSC. The diagnostic criteria for TSC suggest that it can be diagnosed by identifying a heterozygous pathogenic variant of TSC1 or TSC2, even in the absence of clinical signs. In a 4-year-old girl, we identified a splicing variant (NM_000548.4: c.2967-1G>T) that she inherited from her father. Neither the girl (patient) nor her father showed typical features of TSC. This variant is located in a NAGNAG acceptor, which can produce mRNA isoforms that differ by a three-nucleotide indel. Reverse transcription polymerase chain reaction analysis of the patient and both parents' blood RNA samples suggested two different splicing patterns, and these two splicing patterns differed in the presence or absence of the first codon of exon 27, thus providing two splicing products designated as isoforms A and B, respectively. Furthermore, the proportions of these two patterns varied between the patient and either parent. A minigene assay further confirmed that the c.2967-1G>T variant led to the absence of isoform A (including the first codon of exon 27). The finding of our study demonstrates this variant, c.2967-1G>T, disrupts the balance of an alternative splice event which involves the use of two tandem alternatives acceptors and is not associated with typical symptoms of tuberous sclerosis. Our finding is of importance for genetic counseling and suggests that we need to be vigilant to avoid misdiagnosis when we encounter such a site.

Adult renal angiomyolipomas: A retrospective analysis of the histological subtypes and their clinicoradiological correlates

Background

Renal angiomyolipomas (AMLs) are rare, benign mesenchymal tumors of the kidney. Asian data on the prevalence of the subtypes of AMLs and their association with tuberous sclerosis are sparse prompting us to evaluate the clinicopathological characteristics of these tumors.

Materials and Methods

We included cases diagnosed from 2001 to 2021 extracting demographic details, clinical presentation, syndromic association with tuberous sclerosis, and preoperative clinicoradiological features from the electronic medical records.

Results

Ninety-five cases of adult renal AML were diagnosed among 2402 renal tumors, a prevalence of 3.95%. Forty tumors (42%) were detected incidentally; two patients had life-threatening retroperitoneal hemorrhage. Tuberous sclerosis complex (TSC) was associated with ten cases (10.5%). These patients were a decade younger than those in the non-TSC group (P = 0.008) and had bilateral, multiple, and larger tumors (P = 0.0009, 0.001, and 0.047, respectively). Microscopically, classic and epithelioid subtypes were seen in 87 (91.6%) and 8 cases (8.4%), respectively. Hemorrhage was more common in the epithelioid subtype (P = 0.13). HMB-45, melan-A, and smooth muscle actin immunohistochemistry were useful in cases which lacked the prototypical classic histology and for confirming a diagnosis of epithelioid AML.

Conclusions

The prevalence of renal AML in our series was four times higher, and the mean age at diagnosis was a decade earlier than that reported in Western literature but similar to data from two Asian countries. Similar studies from other countries will help ascertain if these differences in prevalence can be attributed to ethnic differences.

Mechanistic target of rapamycin signaling in human nervous system development and disease

Mechanistic target of rapamycin (mTOR) is a highly conserved serine/threonine kinase that regulates fundamental cellular processes including growth control, autophagy and metabolism. mTOR has key functions in nervous system development and mis-regulation of mTOR signaling causes aberrant neurodevelopment and neurological diseases, collectively called mTORopathies. In this mini review we discuss recent studies that have deepened our understanding of the key roles of the mTOR pathway in human nervous system development and disease. Recent advances in single-cell transcriptomics have been exploited to reveal specific roles for mTOR signaling in human cortical development that may have contributed to the evolutionary divergence from our primate ancestors. Cerebral organoid technology has been utilized to show that mTOR signaling is active in and regulates outer radial glial cells (RGCs), a population of neural stem cells that distinguish the human developing cortex. mTOR signaling has a well-established role in hamartoma syndromes such as tuberous sclerosis complex (TSC) and other mTORopathies. New ultra-sensitive techniques for identification of somatic mTOR pathway mutations have shed light on the neurodevelopmental origin and phenotypic heterogeneity seen in mTORopathy patients. These emerging studies suggest that mTOR signaling may facilitate developmental processes specific to human cortical development but also, when mis-regulated, cause cortical malformations and neurological disease.

Leiomyomatosis-like lymphangioleiomyomatosis: A case report of the colonic manifestation of tuberous sclerosis

INTRODUCTION

Tuberous sclerosis complex is an inherited multisystemic disorder with manifestations in various organ systems as a result of a mutation of 1 of 2 tumor suppressor genes, tuberous sclerosis complex-1 or tuberous sclerosis complex-2. Perivascular epithelioid cell tumors have been shown to be associated with these gene mutations and include a variety of tumors such as angiomyolipomas and lymphangioleiomyomatosis.

PATIENT CONCERNS

In this report, we present a case of a 28-year-old woman presenting with symptoms of severe abdominal pain and nausea with a medical history of cardiac rhabdomyoma, adenoma sebaceum, Ash leaf spots, bilateral renal angiomyolipomas, and retinal hamartoma, which are manifestations of tuberous sclerosis complex. The patient was operated twice for colonic perforations in the rectosigmoid and ileocecal regions where the pathologic examination revealed multiple tumoral lesions in both specimens.

DIAGNOSIS

The tumor consisted of a myomatous component where the nodules were composed of spindle cells with fascicular array, and a lymphangiomatous component where epithelioid cells could be observed. Immunohistochemically, smooth muscle markers (desmin and SMA) were positive and the epithelioid component showed HMB-45 positivity. A diagnosis of leiomyomatosis-like lymphangioleiomyomatosis was established due to its morphological and immunohistochemical features, the presence of the tumor in multiple foci, and widespread lymphovascular invasion.

INTERVENTIONS

The patient had a perforation in her bowel twice during the hospital stay and underwent Hartmann operation and ileocecal resection in 2 different surgical operations.

OUTCOMES

After the second operation the patient developed fever and was diagnosed with SARS-CoV-2 infection. No other complication was observed during her stay and the patient's follow-up was unremarkable.

CONCLUSION

Perivascular epithelioid cell tumors are associated with tuberous sclerosis and can rarely appear in the colon. Therefore, lymphangioleiomyomatosis should be in the differential diagnosis in a tuberous sclerosis patient presenting with a colonic tumor.

Birth Characteristics Among Children Diagnosed with Neurofibromatosis Type 1 and Tuberous Sclerosis

OBJECTIVE

To evaluate whether children with neurofibromatosis type 1 (NF1) and tuberous sclerosis have different birth characteristics compared with the general population.

STUDY DESIGN

We identified all individuals born in Sweden between 1973 and 2014 from the nationwide Medical Birth Register for whom information on both biological parents was available (n = 4 242 122). Individuals with NF1 and individuals with tuberous sclerosis were identified using data from Swedish population-based health data registers. Using logistic regression models, we assessed the associations between these 2 neurocutaneous syndromes and birth characteristics in a cohort that included 1804 subjects with NF1 and 450 with tuberous sclerosis.

RESULTS

Children with NF1 and tuberous sclerosis were significantly more likely to be born preterm and via cesarean delivery. In addition, children with NF1 were also more likely to be born with other birth characteristics, such as short length, a large head circumference, and a low Apgar score. Moreover, children with NF1 had an increased odds of being born with a high birth weight or large for gestational age (OR, 1.61; 95% CI, 1.42-1.82 and OR, 1.82; 95% CI, 1.60-2.06, respectively).

CONCLUSION

Children with NF1 and tuberous sclerosis differ from the general population in terms of several birth characteristics, with the strongest associations observed for high birth weight and large for gestational age in individuals with NF1.