2nd NIH Conference on Holoprosencephaly and Early Embryonic Development

Siobhan Dolan, MD


June 07, 2002

In This Article

Concluding Remarks

Dr. Muenke concluded the conference by speaking on the genetic and environmental causes of HPE. He asked us to consider 2 thoughts as we began to head for home.


  1. We generally ascribe to a multi-hit hypothesis of developmental anomalies: that mutations in 2 or more genes (or modifying factors such as maternal diabetes or low cholesterol) affect the penetrance and/or expressivity of developmental anomalies. This helps us understand why different family members have varying severity of disease and has tremendous implications for genetic counseling.

  2. How does low maternal cholesterol affect the developing child? If we hypothesize that low maternal cholesterol adversely affects the brain, we have significant public health work to do to reverse the message about the evil of cholesterol in our diets. Currently, a retrospective study is under way looking at cholesterol levels in the blood samples from second-trimester serum screens and birth outcomes. Preliminary data on 500 mothers reveals that mothers with a low cholesterol had children with a smaller head circumference. A prospective population-based study of maternal cholesterol and clinical outcomes in children is being undertaken in the United Kingdom. This study is collecting detailed outcome data on the infants such as developmental outcomes and school performance and correlating the maternal cholesterol level during pregnancy with the outcomes in children. This study promises to provide the next piece in the puzzle of cholesterol and early embryonic development.


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