Many studies have examined whether early onset, type and severity of epilepsy associates with intellectual ability. Academic issues occur even in people with TSC who have normal intellectual ability. These are often specific learning disorders such as dyscalculia (understanding mathematics), but also include other aspects affecting school life such as anxiety, lack of social skills or low self-esteem.About half of people with TSC, when assessed for neuropsychological skills, are in the bottom 5th percentile in some areas, which indicates a severe impairment. These include problems with attention (for example, being able to concentrate on two separate things like looking and listening), memory (particularly recall, verbal and spatial working memory) and executive function (for example, planning, self-monitoring, cognitive flexibility).The psychosocial impacts of TSC include low self-esteem and self-efficacy in the individual, and a burden on the family coping with a complex and unpredictable disorder. Kidneys
Between 60 and 80% of TSC patients have benign tumors (once thought hamartomatous, but now considered true neoplasms) of the kidneys called angiomyolipomas frequently causing hematuria. These tumors are composed of vascular (angio–), smooth muscle (–myo–), and fat (–lip-) tissue. Although benign, an angiomyolipoma larger than 4 cm is at risk for a potentially catastrophic hemorrhage either spontaneously or with minimal trauma. Angiomyolipomas are found in about one in 300 people without TSC. However, those are usually solitary, whereas in TSC they are commonly multiple and bilateral.About 20-30% of people with TSC have renal cysts, causing few problems.
Genetics
TSC is a genetic disorder with an autosomal dominant pattern of inheritance, variable expressivity, and incomplete penetrance. Two-thirds of TSC cases result from sporadic genetic mutations, not inheritance, but their offspring may inherit it from them. Current genetic tests have difficulty locating the mutation in roughly 20% of individuals diagnosed with the disease. So far, it has been mapped to two genetic loci, TSC1 and TSC2.TSC1 encodes for the protein hamartin, is located on chromosome 9 q34, and was discovered in 1997. TSC2 encodes for the protein tuberin, is located on chromosome 16 p13.3, and was discovered in 1993. TSC2 is contiguous with PKD1, the gene involved in one form of polycystic kidney disease (PKD). Gross deletions affecting both genes may account for the 2% of individuals with TSC who also develop polycystic kidney disease in childhood. TSC2 has been associated with a more severe form of TSC. However, the difference is subtle and cannot be used to identify the mutation clinically. Estimates of the proportion of TSC caused by TSC2 range from 55% to 90%.TSC1 and TSC2 are both tumor suppressor genes that function according to Knudsons "two hit" hypothesis. That is, a second random mutation must occur before a tumor can develop. This explains why, despite its high penetrance, TSC has wide expressivity. Pathophysiology
Hamartin and tuberin function as a complex which is involved in the control of cell growth and cell division.