RISK FACTORS FOR THE DEVELOPMENT OF HOLOPROSENCEPHALY: A MANITOBA-BASED CASE-CONTROL STUDY

Objectives: To examine potential risk factors contributing to the occurrence of holoprosencephaly (HPE) in Manitoba.

Methods: Using a case-control study design, cases of HPE were identified from the Genetics database. Suitable controls matched for gender and birth date were selected randomly from the database. The association of various risk factors with the development of non-syndromic forms of HPE in comparison to controls was examined. Odds ratios and their 95% confidence intervals were calculated.

Results: There were 47 cases of HPE, of whom 23 were identified as non-syndromic, and 47 controls. No statistically significant differences were noted in the mean maternal and paternal age of cases and controls. The crude odds ratios with 95% confidence intervals for various risk factors examined in non-syndromic cases versus controls include: having an Aboriginal mother 3.5 (1.1 to 11.1), an Aboriginal father 12.8 (3.0 to 55.1), or an Aboriginal parent 6.0 (2.5 to 14.3), the presence of a family history of a midline facial defect 8.2 (1.5 to 45.2), and being of low socioeconomic status 3.0 (1.0 to 9.1), all of which significantly increased the risk. Other factors examined, such as the occurrence of previous spontaneous abortion, stillbirth, neonatal death, pre-pregnancy diabetes, infections during pregnancy, alcohol exposure, smoking, and substance abuse, did not attain statistical significance. The use of periconceptional folic acid or vitamins did not exert a protective influence.

Conclusion: Aboriginal background in a parent, family history of a midline facial defect and low socioeconomic status represent significant risk factors in the Manitoba population for the development of HPE. Further prospective studies are necessary to elucidate this association.