What are the clinical features of tuberous sclerosis complex?

Tuberous Sclerosis Complex: Clinical Features

Tuberous sclerosis complex is a multisystem autosomal dominant disorder characterized by proliferative lesions throughout the body, with the classic triad of facial angiofibromas, developmental delay, and intractable epilepsy present in less than 40% of patients. 1

Neurological Manifestations

The neurological features dominate the clinical picture and represent the primary source of morbidity:

• Seizures: Present in approximately 93.7% of patients 2, including:

  • Infantile epileptic spasms syndrome (IESS/West syndrome)
  • Focal epilepsy
  • Drug-resistant epilepsy
  • Status epilepticus (a leading cause of mortality)

• Brain structural lesions:

  • Cortical tubers (present in 100% of cases) 2
  • Subependymal nodules (92.4% of patients) 2
  • Subependymal giant cell astrocytomas (SEGAs) - found in 54% of examined patients 2

• Neuropsychiatric disorders (TAND): Affect 63.3% of patients 2 and include:

  • Autism spectrum disorder
  • Intellectual disability/cognitive impairment
  • Developmental delays
  • Behavioral disorders

Critical pitfall: The correlation between seizures and psychological disorders is significant (p = 0.002) 2, emphasizing that seizure control directly impacts neurodevelopmental outcomes and quality of life.

Dermatological Features

Skin manifestations are nearly universal and often the first recognized signs:

• Hypopigmented macules (ash-leaf spots): Present in 100% of cases 2
• Facial angiofibromas: Part of the classic triad 1
• Shagreen patches
• Ungual fibromas

Renal Manifestations

Kidney involvement is the most common cause of death in adults with TSC 1, with three major phenotypes:

• Angiomyolipomas: 70-80% of patients 1

  • Median detection age: 8-13 years
  • Can develop in first months of life
  • Risk of hemorrhage and kidney failure

• Cystic kidney disease: ~50% of patients 1

  • Median detection age: 3 years
  • Can also present in infancy

• Renal cell carcinoma/oncocytoma: 3-5% of patients 1

Approximately 40% of adult TSC patients develop low GFR 1, making kidney disease a critical determinant of long-term survival.

Cardiac Manifestations

• Cardiac rhabdomyomas: Present in 41.3% of patients 2
• Often detected prenatally or in infancy
• May regress spontaneously but can cause arrhythmias or obstruction

Pulmonary Manifestations

• Lymphangioleiomyomatosis (LAM): Primarily affects women
• Progressive cystic lung disease
• Can lead to respiratory failure

Ophthalmologic Features

• Retinal hamartomas: Found in 42.9% of examined patients 2
• Usually asymptomatic but important diagnostic markers

Malignancy Risk

Beyond organ-specific tumors, TSC carries cancer risks:

• Thyroid cancer: The predominant malignancy risk in childhood
  • Differentiated thyroid cancer occurs in up to one-third of PHTS patients
  • Earliest reported case at 7 years of age
  • 5% of individuals under 20 develop thyroid cancer 3

Genetic Basis

TSC results from mutations in TSC1 or TSC2 genes 4, causing dysregulation of the mTOR pathway, which explains the proliferative nature of lesions across all organ systems.

Key Clinical Considerations

The disease has an incidence of approximately 1 in 5,800 births 1, affecting over one million people worldwide. The leading causes of mortality across all ages are:

1. Epilepsy (especially status epilepticus and sudden unexpected death in epilepsy)
2. Kidney complications
3. Complications from infections 1

Critical surveillance point: Normal kidney imaging and GFR in young children do not preclude future development of kidney lesions 1. All TSC patients require lifelong monitoring starting from diagnosis, as lesions develop progressively with age.

The wide phenotypic variability means TSC is frequently unrecognized, requiring high clinical suspicion and systematic evaluation of all organ systems even in asymptomatic patients 2.