Congenital Hydrocephalus in Mono and Dizygotic Twins

Background: Information regarding the occurrence of hydrocephalus (HC) in twins is important in establishing the significance of environmental factors as well as a genetic basis in congenital HC aetiology. This was the basis for this study.
Methods: A single institution retrospective study was conducted between August 1, 2006 and July 31, 2008. Only those cases of hydrocephalus (based on clinical and radiological testscranial Computeried tomographic or Magnetic resonance imaging scan) that required placement of a ventricular shunt or endoscopic third ventriculostomy were included in the study. Data regarding the patient’s demographics, clinical history, examination and the maternal demographics were retrieved and analysed. DNA analysis was done to confirm the fraternity of the twins when applicable.
Results: Fifty-eight patients with congenital hydrocephalus presented to the unit over the study period. We identified three sets of twins in the study. Only one set were identical (both male) and both had hydrocephalus. In the remaining two sets only one out of each pair had hydrocephalus (one male and one female). Two of the patients (1male, 1female) were twins with discordant HC. All the children had normal thumbs. DNA analysis confirmed identical twins in both the like sex twins. The mothers were not known diabetics, hypertensive or sickle cell patients neither did they smoke or take alcohol. There was no family history of hydrocephalus in all patients.
Conclusion: Concordance for HC is likely if the twins are like sex and identical. Congenital hydrocephalus seems to be a multifactorial disorder, triggered by environmental factors in genetically predisposed individuals.