Vertigo.

Family and adoption studies indicate that genetic factors play a role in the development of many psychiatric disorders. A variable number of possible interacting genes giving a predisposition to the diseases is likely. The genetic dissection has been hampered by genetic complexity as well as by difficulties in defining the phenotypes. Genetic mapping efforts using sib pairs, twins and individual large families have revealed preliminary or tentative evidence of susceptibility loci for a number of psychiatric disorders. Illnesses described in this article include the prion disease familial fatal insomnia (FFI), alcoholism, anorexia nervosa, autism, bipolar affective disorder, dyslexia, enuresis nocturna, epilepsia, obsessive-compulsive disorders (OCD), schizophrenia, and the dementias, Alzheimer's disease and frontal lobe dementia. The genes and proteins related to the newly discovered transmitter in the central nervous system, nitric oxide (NO), and its genes and proteins are also reviewed. The number of mapped human genes now exceeds 30,000 of the estimated total number of 60,000 to 100,000 genes. This rapid development will facilitate gene mapping and efforts to isolate and identify the genes responsible for symptom susceptibility in many of the aetiologically unclear psychiatric diseases with complex genetic origin.

Central Nervous System Diseases↗

PubMed1999

Elejalde syndrome--a melanolysosomal neurocutaneous syndrome: clinical and morphological findings in 7 patients.

BACKGROUND: Silvery hair and severe dysfunction of the central nervous system (neuroectodermal melanolysosomal disease or Elejalde syndrome) characterize this rare autosomal recessive disease. Main clinical features include silver-leaden hair, bronze skin after sun exposure, and neurologic involvement (seizures, severe hypotonia, and mental retardation). Large granules of melanin unevenly distributed in the hair shaft are observed. Abnormal melanocytes and melanosomes and abnormal inclusion bodies in fibroblasts may be present. Differential diagnosis with Chédiak-Higashi syndrome and Griscelli syndrome must be done. OBSERVATIONS: We studied pediatric patients with silvery hair and profound neurologic dysfunction. Immune impairment was absent. Age of onset of neurologic signs ranged from 1 month to 11 years; the signs included severe muscular hypotonia, ocular alterations, and seizures. Mental retardation since the first months of life was noted in 4 cases. Psychomotor development was normal in 3 cases, but suddenly the patients presented with a regressive neurologic process. Four patients died between 6 months and 3 years after the onset of neurologic dysfunction. One patient showed characteristic ultrastructural findings of Elejalde syndrome. CONCLUSIONS: Elejalde syndrome is different from Chédiak-Higashi and Griscelli syndrome and is characterized by silvery hair and frequent occurrence of fatal neurologic alterations. Psychomotor impairment may have 2 forms of presentation: congenital or infantile. Although Elejalde syndrome and Griscelli syndrome are similar, the possibility that they are 2 different diseases, although probably allelic related, is suggested.

Central Nervous System Diseases↗