What causes holoprosencephaly malformation complex?

Genetic abnormalities: About 25-50% of HPE cases are associated with structural or numerical chromosomal abnormalities. Many patients have karyotypes, or abnormal numbers of chromosomes. Chromosomes contain a person's genetic makeup. Each person has 23 pairs of chromosomes. HPE is most commonly associated with an extra copy of chromosome 13 (called trisomy 13), an extra copy of chromosome 18 (called trisomy 18), and an extra copy of chromosome 15 (called trisomy 15). Researchers believe that HPE might be linked to as many as 12 chromosomal regions on 11 different chromosomes. Genetic abnormalities associated with HPE may occur randomly or they may be passed down among families.

Diabetic mother: According to the National Institute of Neurological Disorders and Stroke (NINDS), children of diabetic mothers appear to have an increased risk of having HPE.

History of miscarriage: It has been suggested that mothers who have had previous miscarriages and bleeding during the first trimester of pregnancy may have an increased risk of having children with HPE.

Infections during pregnancy: Certain infections, including herpes, syphilis, cytomegalovirus, rubella, and toxoplasmosis, have been associated with HPE. However, it is unclear if these infections actually cause HPE.

Medications during pregnancy: Certain medications, including alcohol, aspirin, lithium, thorazine, anticonvulsants, hormones, retinoic acid, and nicotine, have been suggested as possible risk factors for HPE.