A consensus conference sponsored by the National Institutes of Health and the National Tuberous Sclerosis (TS) Association in July 1998 provided a revised list of diagnostic criteria of TS. The major and minor features are as follows: Major features: facial angiofibromas, ungual fibroma, >3 hypomelanotic macules, shagreen patch, retinal hamartomas, cortical tuber, subependymal astrocytoma, cardiac rhabdomyoma, lymphangiomyomatosis, renal angiomyolipoma.
Minor features: dental enamel pits, rectal polyps, bone cysts, white matter migration tracts, gingival fibromas, nonrenal hamartoma, retinal achromic patch, confetti skin lesions, multiple renal cysts.
Definite TS Complex: 2 major or 1 major with 2 minor features.
Probable TSC: 1 major and 1 minor feature.
Possible TSC: 1 major feature or 2 or more minor features.
The diagnosis of TSC is frequently made on dermatological evidence, and examination with UV light is used in screening asymptomatic relatives. Genetic criteria are not included and genetic testing is unavailable. Two genes account for TSC, TSC1 found on chromosome 9, and TSC2 on chromosome 16, both transmitted as autosomal dominants. Affected children of asymptomatic parents are explained by germline mosaicism. Sporadic cases make up two thirds of TSC patients, and 75% are caused by TSC2 mutations. [1]
COMMENT. Dermatological features are important among the diagnostic criteria for tuberous sclerosis complex. Four major and 1 minor required criteria are dermatologic. Renal and retinal hamartomas are also major diagnostic features. Genetic criteria are not included in the list of diagnostic features.