Diagnosis
There are no pathognomonic clinical signs for tuberous sclerosis. Many signs are present in individuals who are healthy (although rarely), or who have another disease. A combination of signs, classified as major or minor, is required in order to establish a clinical diagnosis.
| Major Features | ||||
|---|---|---|---|---|
| Location | Sign | Onset | Note | |
| 1 | Head | Facial angiofibromas or forehead plaque | Infant – adult | |
| 2 | Fingers and toes | Nontraumatic ungual or periungual fibroma | Adolescent – adult | |
| 3 | Skin | Hypomelanotic macules | Infant – child | More than three. |
| 4 | Skin | Shagreen patch (connective tissue nevus) | Child | |
| 5 | Brain | Cortical tuber | Fetus | |
| 6 | Brain | Subependymal nodule | Child – adolescent | |
| 7 | Brain | Subependymal giant cell astrocytoma | Child – adolescent | |
| 8 | Eyes | Multiple retinal nodular hamartomas | Infant | |
| 9 | Heart | Cardiac rhabdomyoma | Fetus | Single or multiple. |
| 10 | Lungs | Lymphangioleiomyomatosis | Adolescent – adult | |
| 11 | Kidneys | Renal angiomyolipoma | Child – adult | 10 and 11 together count as one major feature. |
| Minor Features | ||||
| Location | Sign | Note | ||
| 12 | Teeth | Multiple randomly distributed pits in dental enamel | ||
| 13 | Rectum | Hamartomatous rectal polyps | Histologic confirmation is suggested. | |
| 14 | Bones | Bone cysts | ||
| 15 | Brain | Cerebral white-matter "migration tracts" | Radiographic confirmation is sufficient. 5 and 15 together count as one major feature. | |
| 16 | Gums | Gingival fibromas | ||
| 17 | Liver, spleen and other organs | Nonrenal hamartoma | Histologic confirmation is suggested. | |
| 18 | Eyes | Retinal achromic patch | ||
| 19 | Skin | "Confetti" skin lesions | ||
| 20 | Kidneys | Multiple renal cysts | Histologic confirmation is suggested. | |
In infants, the first clue is often the presence of seizures, delayed development or white patches on the skin. A full clinical diagnosis involves
- Taking a personal and family history.
- Examining the skin under a Wood's lamp (hypomelanotic macules), the fingers and toes (ungual fibroma), the face (angiofibromas) and the mouth (dental pits and gingival fibromas).
- Cranial imaging with non enhanced CT or, preferably, MRI (cortical tubers and subependymal nodules).
- Renal ultrasound (angiomyolipoma or cysts).
- An echocardiogram in infants (rhabdomyoma).
- Fundoscopy (retinal nodular hamartomas or achromic patch).
The various signs are then marked against the diagnostic criteria to produce a level of diagnostic certainty:
- Definite – Either two major features or one major feature plus two minor features.
- Probable – One major plus one minor feature.
- Suspect – Either one major feature or two or more minor features.
Due to the wide variety of mutations leading to TSC, there are no simple genetic tests available to identify new cases. Nor are there any biochemical markers for the gene defects. However, once a person has been clinically diagnosed, the genetic mutation can usually be found. The search is time-consuming and has a 15% failure rate, which is thought to be due to somatic mosaicism. If successful, this information can be used to identify affected family members, including prenatal diagnosis. As of 2006, preimplantation diagnosis is not widely available.
Read more about this topic: Tuberous Sclerosis