Tuberous Sclerosis Complex in Chinese patients: Phenotypic analysis and mutational screening of TSC1/TSC2 genes

Clinical practice recommendations for kidney involvement in tuberous sclerosis complex: a consensus statement by the ERKNet Working Group for Autosomal Dominant Structural Kidney Disorders and the ERA Genes & Kidney Working Group

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the presence of proliferative lesions throughout the body. Management of TSC is challenging because patients have a multifaceted systemic illness with prominent neurological and developmental impact as well as potentially severe kidney, heart and lung phenotypes; however, every organ system can be involved. Adequate care for patients with TSC requires a coordinated effort involving a multidisciplinary team of clinicians and support staff. This clinical practice recommendation was developed by nephrologists, urologists, paediatric radiologists, interventional radiologists, geneticists, pathologists, and patient and family group representatives, with a focus on TSC-associated kidney manifestations. Careful monitoring of kidney function and assessment of kidney structural lesions by imaging enable early interventions that can preserve kidney function through targeted approaches. Here, we summarize the current evidence and present recommendations for the multidisciplinary management of kidney involvement in TSC.

Tsc2 mutation rather than Tsc1 mutation dominantly causes a social deficit in a mouse model of tuberous sclerosis complex

BACKGROUND

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that is associated with neurological symptoms, including autism spectrum disorder. Tuberous sclerosis complex is caused by pathogenic germline mutations of either the TSC1 or TSC2 gene, but somatic mutations were identified in both genes, and the combined effects of TSC1 and TSC2 mutations have been unknown.

METHODS

The present study investigated social behaviors by the social interaction test and three-chambered sociability tests, effects of rapamycin treatment, and gene expression profiles with a gene expression microarray in Tsc1 and Tsc2 double heterozygous mutant (TscD^+/-) mice.

RESULTS

TscD^+/- mice exhibited impairments in social behaviors, and the severity of impairments was similar to Tsc2^+/- mice rather than Tsc1^+/- mice. Impairments in social behaviors were rescued by rapamycin treatment in all mutant mice. Gene expression profiles in the brain were greatly altered in TscD^+/- mice more than in Tsc1^+/- and Tsc2^+/- mice. The gene expression changes compared with wild type (WT) mice were similar between TscD^+/- and Tsc2^+/- mice, and the overlapping genes whose expression was altered in mutant mice compared with WT mice were enriched in the neoplasm- and inflammation-related canonical pathways. The "signal transducer and activator of transcription 3, interferon regulatory factor 1, interferon regulatory factor 4, interleukin-2R α chain, and interferon-γ" signaling pathway, which is initiated from signal transducer and activator of transcription 4 and PDZ and LIM domain protein 2, was associated with impairments in social behaviors in all mutant mice.

LIMITATIONS

It is unclear whether the signaling pathway also plays a critical role in autism spectrum disorders not caused by Tsc1 and Tsc2 mutations.

CONCLUSIONS

These findings suggest that TSC1 and TSC2 double mutations cause autistic behaviors similarly to TSC2 mutations, although significant changes in gene expression were attributable to the double mutations. These findings contribute to the knowledge of genotype-phenotype correlations in TSC and suggest that mutations in both the TSC1 and TSC2 genes act in concert to cause neurological symptoms, including autism spectrum disorder.

Progress of clinical research studies on tuberous sclerosis complex-related epilepsy in China

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous syndrome, with 75.6%-83.5% and 54.1% patients presenting with epilepsy and drug-resistant epilepsy (DRE), respectively. Clinical studies on TSC, particularly surgical interventions, have achieved rapid and substantial progress. The TSC-Task Force Committee of the China Association Against Epilepsy (CAAE-TFTSC) was founded in 2012, and annual academic conferences on the surgical treatment of TSC-related epilepsy have been held since 2013. 'China experts' consensus on surgical treatment of TSC-related epilepsy' was published in 2019. This review focuses on surgical treatment, including resective surgery, neuromodulations, corpus callosotomy and mini-invasive ablations, as well as studies on phenotype, genotype and anti-seizure therapies of mammalian target of rapamycin inhibitor, vigabatrin and ketogenic diet in patients with TSC-related DRE in China.

Genotype/phenotype correlation in 123 Chinese patients with Tuberous Sclerosis Complex

Tuberous Sclerosis Complex (TSC) is a multisystemic neurocutaneous disorder with autosomal dominant inheritance. We performed mutation analyses on 123 Chinese patients with "definite TSC" according to the latest diagnostic criteria. Pathogenic / likely-pathogenic variants were identified in 72.2% of all index patients (70/97), in which 35.7% (25/70) had TSC1 variants and 64.3% (45/70) had TSC2 variants. 84.5% (82/97) cases were sporadic and 15.5% (15/97) cases were familial. 62 unique variants were reported, in which 41.9% (26/62) were novel. Male patients had significantly more subependymal nodules (p=0.029) than females, whereas renal angiomyolipoma (p=0.032) occurred predominantly in females. Sporadic cases also had more renal angiomyolipoma (p=0.004), cortical tubers (p=0.008), hypopigmented macules (p=0.018) and fibrous cephalic plaques (p=0.028) than cases with known inheritance. Patients with TSC2 pathogenic variants were more likely to have mental retardation (p<0.001), cardiac rhabdomyoma (p=0.004), renal angiomyolipoma (p=0.006) and facial angiofibromas (p=0.026) than those with TSC1 pathogenic variants, while mutation-negative cases showed a mixed phenotype between those with TSC1 and TSC2 variants. There were no significant phenotypic differences between patients with and without TSC1/TSC2 variants, but TSC2 missense and in-frame variants were associated with higher frequencies of mental retardation (P<0.001), renal angiomyolipoma (p=0.001), cardiac rhabdomyoma (p=0.012) and facial angiofibroma (p=0.021) than those with TSC1 frameshift and splice site variants. Furthermore, a higher frequency of mental retardation (p=0.013) was observed in patients with TSC2 missense and in-frame variants than those with frameshift and splice site variants. All 14 antenatal-onset patients had cardiac rhabdomyoma. They had fewer seizures (p=0.028) than patients with paediatric-onset, but were more likely to have mental retardation (p=0.035) than individuals with adult-onset disease. Generally, paediatric-onset patients had more neurological manifestations, while initial presentations of adult-onset TSC were more diverse.

The association of neurodevelopmental abnormalities, congenital heart and renal defects in a tuberous sclerosis complex patient cohort

BACKGROUND

Tuberous sclerosis complex (TSC) is a rare multi-system genetic disorder characterised by the presence of benign tumours throughout multiple organs including the brain, kidneys, heart, liver, eyes, lungs and skin, in addition to neurological and neuropsychiatric complications. Intracardiac tumour (rhabdomyoma), neurodevelopmental disorders (NDDs) and kidney disorders (KD) are common manifestations of TSC and have been linked with TSC1 and TSC2 loss-of-function mutations independently, but the dynamic relationship between these organ manifestations remains unexplored. Therefore, this study aims to characterise the nature of the relationship specifically between these three organs' manifestations in TSC1 and TSC2 mutation patients.

METHODS

Clinical data gathered from TSC patients across South Wales registered with Cardiff and Vale University Health Board (CAV UHB) between 1990 and 2020 were analysed retrospectively to evaluate abnormalities in the heart, brain and kidney development. TSC-related abnormalities such as tumour prevalence, location and size were analysed for each organ in addition to neuropsychiatric involvement and were compared between TSC1 and TSC2 mutant genotypes. Lastly, statistical co-occurrence between organ manifestations co-morbidity was quantified, and trajectories of disease progression throughout organs were modelled.

RESULTS

This study found a significantly greater mutational frequency at the TSC2 locus in the cohort in comparison to TSC1. An equal proportion of male and female patients were observed in this group and by meta-analysis of previous studies. No significant difference in characterisation of heart involvement was observed between TSC1 and TSC2 patients. Brain involvement was seen with increased severity in TSC2 patients, characterised by a greater prevalence of cortical tubers and communication disorders. Renal pathology was further enhanced in TSC2 patients, marked by increased bilateral angiomyolipoma prevalence. Furthermore, co-occurrence of NDDs and KDs was the most positively correlated out of investigated manifestations, regardless of genotype. Analysis of disease trajectories revealed a more diverse clinical outcome for TSC2 patients: however, a chronological association of rhabdomyoma, NDD and KD was most frequently observed for TSC1 patients.

CONCLUSIONS

This study marks the first empirical investigation of the co-morbidity between congenital heart defects (CHD), NDDs, and KDs in TSC1 and TSC2 patients. This remains a unique first step towards the characterisation of the dynamic role between genetics, heart function, brain function and kidney function during the early development in the context of TSC.

Diagnostic features of tuberous sclerosis complex: case report and literature review

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic syndrome that is caused by mutations in the tumour suppressor genes TSC1 or TSC2 which causes multiorgan growths. TSC presents at any age as a wide range of clinical and phenotypic manifestations with varying severity. The main goal of this article was to state two cases of TSC and review the most commonly reported major and minor diagnostic clinical features and the most common features that led to an investigation of possible TSC diagnosis. Herein, we report two cases of TSC, which both presented with seizures during the first 6 months of life. Case 1 presented with multiple types of seizures from 6 months of age and was diagnosed by multiple calcified subependymal nodules (SENs) detected by computed tomography and magnetic resonance imaging (MRI). Case 2 presented with seizures from 3 months of age and was diagnosed prenatally when a tumour was seen in her heart during antenatal ultrasonography. In conclusion, the literature review revealed that neurological manifestations (mainly seizures) were the main feature that led to investigation and diagnosis of TSC followed by abdominal manifestations (mainly renal features) and antenatal follow-up imaging. Other manifestations in skin, chest, eyes, teeth and heart rarely led to TSC diagnosis. In some cases, TSC was incidentally discovered by medical imaging. The cortical tubers, SENs, and subependymal giant cell astrocytomas brain lesions were the most commonly reported major features. Skin features including angiofibromas, ungual fibromas and shagreen patch were the second most common major features reported in the literature. However, skin manifestations were not a common led to investigation and diagnosis of TSC. Renal features, mainly angiomyolipomas (AMLs), were the third most common major feature reported. Medical imaging plays an essential role in diagnosis of TSC, and clinical features are important clues that lead to investigation for the disease.

An Israeli tuberous sclerosis cohort: the efficacy of different anti-epileptic strategies

AIM

We aimed to describe the experience of a large single-center cohort for the clinical, radiological, and genetic characteristics, as well as to determine the efficacy of different anti-epileptic strategies in children and adults with tuberous sclerosis complex (TSC).

METHODS

We carried out a historical cohort study on 91 TSC patients treated in a single center between 2008 and 2018.

RESULTS

Our cohort comprised 46 males and 45 females, with a median age of 15.6 years at the last follow-up. Mean follow-up time was 2.5 ± 0.75-5.5 years (range 0-9.5 years). Of those tested, a disease-causing mutation was identified in 90% of patients, 53% in TSC2, and 37% in TSC1. Epilepsy prevalence was similar among TSC1 and TSC2 mutated patients. The most common radiological finding were cortical tubers in 95% of patients, while subependymal giant cell astrocytoma (SEGA) were detected in 36% of patients. Notably, infantile spasms (IS) were diagnosed in 29%, with SEGA representing the only finding significantly different in prevalence between those with and without IS (62% vs. 28%, respectively, p = 0.009). Lastly, we did not find any difference in efficacy between three anti-epileptic treatments: Vagus nerve stimulation (VNS), CBD-based products, and the ketogenic diet, all showing approximately 30%-40% response rates.

SIGNIFICANCE

Altogether, we provide a comprehensive description of our experience in treating TSC, which could serve to expand current knowledge of the disease and its treatments.

Early diagnosis of a newborn with tuberous sclerosis caused by a genetic mutation

Objective

Tuberous sclerosis (TSC) is an autosomal dominant disorder, often detected during childhood. We present the results of genetic testing in a newborn with suspected TSC.

Methods

A newborn with no specific clinical manifestations of TSC showed evidence of TSC on magnetic resonance imaging and echocardiography. Next-generation sequencing (NGS) and multiple ligation-dependent probe amplification (MLPA) of the TSC1 and TSC2 gene exons were carried out to confirm the diagnosis.

Results

The results of MLPA were negative, but NGS showed a heterozygous mutation in the TSC1 gene comprising insertion of a T residue at c.2165 (exon 17) to c.2166 (exon 17), indicating a loss of function mutation. These results were verified by Sanger sequencing. This genetic change was present in the newborn but the parental genotypes were wild-type, indicating a de novo mutation.

Conclusions

In this case, a case of TSC caused by a heterozygous mutation in the TSC1 gene was confirmed by NGS sequencing. This indicates the suitability of genetic testing for the early diagnosis of clinically rare and difficult-to-diagnose diseases, to guide clinical treatment.

Tuberous Sclerosis Complex: Early Screening and Infant Outcome in NICU

OBJECTIVE

We describe the clinical and genetic features, drug use and neuropsychiatric disorders of infants diagnosed with tuberous sclerosis complex (TSC) within 3 months of age at a neonatal intensive care unit (NICU) to better understand the different outcomes from early screening.

METHODS

In this retrospective study, we consisted of 42 infants with a definitive TSC diagnosis by genetic criteria (TSC1 = 8, TSC2 = 34). The different phenotypes and outcomes between patients with TSC1 and TSC2 mutations were analyzed.

RESULTS

The most common initial presenting features of TSC were cortical tubers on magnetic resonance imaging (50%), hypomelanotic macules on skin (47.61%) and spasm (42.85%), when they were diagnosed. Following disease progression to time of follow-up 1 year later, we found that the rate of epilepsy increased from 42.85% to 75.61% and that of cardiac rhabdomyoma increased from 28.57% to 43.9%. The median age at first presentation was 7.84 ± 1.88 months. We also found that 54.83% of patients on medication were seizure free for over 1 year, and that 43.9% of patients have intellectual disability. In total, 42 variants of TSC were detected, including 12 novel variants. We found no evidence of an association between different clinical features and their outcomes among patients with different gene mutations.

CONCLUSION

Early diagnosis of TSC in NICU opens a window of opportunity for early, more effective treatment of epilepsy as well as reduces the risk of neurological conditions.

Application Areas of Traditional Molecular Genetic Methods and NGS in relation to Hereditary Urological Cancer Diagnosis

Next generation sequencing (NGS) is widely used for diagnosing hereditary cancer syndromes. Often, exome sequencing and extended gene panel approaches are the only means that can be used to detect a pathogenic germline mutation in the case of multiple primary tumors, early onset, a family history of cancer, or a lack of specific signs associated with a particular syndrome. Certain germline mutations of oncogenes and tumor suppressor genes that determine specific clinical phenotypes may occur in mutation hot spots. Diagnosis of such cases, which involve hereditary cancer, does not require NGS, but may be made using PCR and Sanger sequencing. Diagnostic criteria and professional community guidelines developed for hereditary cancers of particular organs should be followed when ordering molecular diagnostic tests for a patient. This review focuses on urological oncology associated with germline mutations. Clinical signs and genetic diagnostic laboratory tests for hereditary forms of renal cell cancer, prostate cancer, and bladder cancer are summarized. While exome sequencing, or, conversely, traditional molecular genetic methods are the procedure of choice in some cases, in most situations, sequencing of multigene panels that are specifically aimed at detecting germline mutations in early onset renal cancer, prostate cancer, and bladder cancer seems to be the basic solution for molecular genetic diagnosis of hereditary cancers.

Mutational analysis of TSC1 and TSC2 in Danish patients with tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by hamartomas in the skin and other organs, including brain, heart, lung, kidney and bones. TSC is caused by mutations in TSC1 and TSC2. Here, we present the TSC1 and TSC2 variants identified in 168 Danish individuals out of a cohort of 327 individuals suspected of TSC. A total of 137 predicted pathogenic or likely pathogenic variants were identified: 33 different TSC1 variants in 42 patients, and 104 different TSC2 variants in 126 patients. In 40 cases (24%), the identified predicted pathogenic variant had not been described previously. In total, 33 novel variants in TSC2 and 7 novel variants in TSC1 were identified. To assist in the classification of 11 TSC2 variants, we investigated the effects of these variants in an in vitro functional assay. Based on the functional results, as well as population and genetic data, we classified 8 variants as likely to be pathogenic and 3 as likely to be benign.