title: Risk of recurrence in major central nervous system malformations between 1976 and 2005.
abstract: OBJECTIVE
  The goal of the current publication is to review isolated central nervous system malformations (CSMs) using a database in excess of 75 000 cases, with special regard to the risk of recurrence of these malformations alone or in combination.
  
  
  METHODS
  In the period between 1 January 1976 and 31 December 2005, among the 75 320 documented cases, consultations were requested due to earlier isolated CSMs in the patients' histories in 3030 cases (4.2%). Processing the data we only considered disorders of genetic origin, and that was why we excluded the cases due to intrauterine infection. Monogenically inherited malformations were also excluded from the analysis. The diagnosis of the malformations was based on the prenatal diagnosis of ultrasonography as well as the findings of the foetopathological examination.
  
  
  RESULTS
  In 65% of the cases, the couples sought counselling because of malformation in a previous pregnancy. In these cases, the risk of recurrence was thought to be 5.2%, while in the case of two affected children this figure stood at 21.9%. Analysing the values for the risk of recurrence in 5-year periods, neural tube defects (NTDs) (particularly anencephaly and spina bifida) showed a detectable decrease, which could be attributed to a growing use of folic acid supplementation around the time of conception and during pregnancy.
  
  
  CONCLUSIONS
  There is a clear decrease of risk of recurrence of NTDs, while in the case of the other CSMs in this study, there is no noteworthy chronological change in their risk of recurrence.
authors: 1st. Department of Obstetrics and Gynecology, Semmelweis University Medical School, Hungary. joogabor@hotmail.com
authors: József Gábor
authors: JG
authors: Joó
authors: Artúr
authors: A
authors: Beke
authors: Zoltán
authors: Z
authors: Papp
authors: Akos
authors: A
authors: Csaba
authors: Attila
authors: A
authors: Rab
authors: Csaba
authors: C
authors: Papp
mesh_terms: D000015:Abnormalities, Multiple / Q000209:etiology*; D002490:Central Nervous System / Q000002:abnormalities*; D002493:Central Nervous System Diseases / Q000151:congenital* / Q000209:etiology*; D016208:Databases, Factual; D005260:Female; D005817:Genetic Counseling; D006801:Humans; D008297:Male; D011247:Pregnancy; D012008:Recurrence; D017584:Reproductive History; D012189:Retrospective Studies; D012307:Risk Factors