rss
J Med Genet 41:203-207 doi:10.1136/jmg.2003.012757
  • Letters to JMG

Genotype and psychological phenotype in tuberous sclerosis

  1. J C Lewis1,
  2. H V Thomas2,
  3. K C Murphy3,
  4. J R Sampson1,4
  1. 1Institute of Medical Genetics, University of Wales College of Medicine, Cardiff, UK
  2. 2Department of Psychological Medicine, University of Wales College of Medicine, Cardiff, UK
  3. 3Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Eire
  4. 4Institute of Medical Genetics, University of Wales College of Medicine, Cardiff, UK
  1. Correspondence to:
 J R Sampson
 Institute of Medical Genetics, University of Wales College of Medicine, Heath Park, Cardiff CF14 4N, UK; sampson @cf.ac.uk
  • Received 23 July 2003
  • Accepted 24 October 2003

Tuberous sclerosis complex (TSC, MIM 191090 and 191100) is an autosomal dominant, multisystem disorder characterised by the development of a variety of hamartomatous growths.1 The TSC phenotype includes renal involvement (in over 80% of patients) with angiomyolipomas and cysts; skin involvement with facial angiofibromas, hypomelanotic macules, shagreen patches, and periungual fibromas; and cardiac, ophthalmic, and pulmonary involvement. Many of the frequent and serious complications of TSC, including epilepsy, mental retardation, and a wide range of psychiatric and behavioural disorders, reflect the cerebral involvement that occurs in over 90% of cases. Structural abnormalities in the brain include: cortical tubers that are localised areas of loss of normal hexalaminar cortical organisation, and that contain abnormal and enlarged cells categorised as cytomegalic neurones and balloon cells; subependymal nodules that are localised proliferations of abnormal cells in the periventricular zone; and migration tracts through the white matter linking subependymal and cortical lesions.

Mental retardation is estimated to occur in approximately 45% of cases.2 It is virtually always associated with a history of seizures correlated with early seizure onset, poor seizure control, and type of seizure at onset with the greatest risk for infantile spasms.3 The association between mental retardation and infantile spasms is particularly strong in the context of TSC.4 People with TSC are also reported to have high rates of autistic disorder, attention deficit hyperactivity disorder (ADHD), and sleep disorder. Although autistic disorder is a feature of several genetic disorders of childhood, its frequency is highest in TSC,5 and the strength of the association does not appear to be explained simply by the frequency of infantile spasms in TSC.6 Sleep disorder in TSC is associated with the presence of other behavioural problems and can be exacerbated by nocturnal seizures.7,8 There are also anecdotal reports of …