Tuberous sclerosis complex

Abstract

Clinical characteristics Tuberous sclerosis complex (TSC) involves abnormalities of the skin (hypomelanotic macules, confetti skin lesions, facial angiofibromas, shagreen patches, fibrous cephalic plaques, ungual fibromas); brain (subependymal nodules, cortical dysplasias, and subependymal giant cell astrocytomas [SEGAs], seizures, intellectual disability / developmental delay, psychiatric illness); kidney (angiomyolipomas, cysts, renal cell carcinomas); heart (rhabdomyomas, arrhythmias); and lungs (lymphangioleiomyomatosis [LAM], multifocal micronodular pneumonocyte hyperplasia). Central nervous system tumors are the leading cause of morbidity and mortality; renal disease is the second leading cause of early death. Diagnosis/testing The diagnosis of TSC is established in a proband with one of the following: Two major clinical features One major clinical feature and two or more minor features Identification of a heterozygous pathogenic variant in TSC1 or TSC2 by molecular genetic testing Management Treatment of manifestations: For enlarging SEGAs: mTOR inhibitors; neurosurgery when size causes life-threatening neurologic symptoms. For seizures: vigabatrin and other anti-seizure medication, and on occasion, epilepsy surgery. For renal angiomyolipomas >4 cm, or >3 cm and growing rapidly: mTOR inhibitors are the recommended first line of therapy with secondary therapy options being embolization, renal sparing surgery, or ablative therapy. For facial angiofibromas: topical mTOR inhibitors. For symptomatic cardiac rhabdomyomas: surgical intervention or consideration of mTOR inhibitor therapy. For LAM: mTOR inhibitors. Prevention of secondary complications: For those on vigabatrin therapy, vision testing within four weeks of therapy initiation, at three-month intervals while on treatment, and three to six months after treatment is discontinued. Surveillance: Brain MRI every one to three years in asymptomatic individuals with TSC younger than age 25 years to monitor for new occurrence of SEGAs; those with asymptomatic SEGA in childhood should continue to be imaged periodically in adulthood; for those with large or growing SEGA or SEGA causing ventricular enlargement, more frequent brain MRIs as deemed clinically appropriate; screening for TSC-associated neuropsychiatric disorder (TAND) at least annually with comprehensive formal evaluation for TAND at key developmental time points; EEG in individuals with known or suspected seizure activity; MRI of the abdomen to assess for progression of angiomyolipoma and renal cystic disease every one to three years; assess renal function (glomerular filtration rate and blood pressure) at least annually; echocardiogram every one to three years in asymptomatic infants and children with cardiac rhabdomyomas until regression is documented; clinical screening for LAM symptoms (exertional dyspnea and shortness of breath) at each clinic visit in women older than age 18 years or those who report respiratory symptoms; high-resolution computed tomography (HRCT) every five to ten years in asymptomatic individuals at risk for LAM (adult females age >18 years) even when there are no signs of LAM on baseline examination; annual pulmonary function testing and HRCT every two to three years for individuals with lung cysts detected by HRCT; annual dermatologic examination; dental examination every six months; annual ophthalmology evaluation in those with previously identified ophthalmologic lesions or vision symptoms. Agents/circumstances to avoid: Smoking; estrogen use; nephrectomy. Evaluation of relatives at risk: Identifying affected relatives enables monitoring for early detection of problems associated with TSC, which leads to earlier treatment and better outcomes. Genetic counseling TSC is inherited in an autosomal dominant manner. Two thirds of affected individuals have TSC as the result of a de novo pathogenic variant. The offspring of an affected individual are at a 50% risk of inheriting the pathogenic variant. If the pathogenic variant has been identified in an affected family member, prenatal testing for a pregnancy at increased risk and preimplantation genetic testing are possible.