Holoprosencephaly refers to failure of left and right hemisphere of the brain to divide properly into two halves. The condition also affects the face and the head. Individuals with nonsyndromic holoprosencephaly can present with microcephaly, macrocephaly, hydrocephalus, cleft lip or palate, depressed nasal bridge, or microphthalmia. In very severe form of nonsyndromic holoprosencephaly, the individual may have cyclopia. Reference: https://medlineplus.gov/genetics/condition/nonsyndromic-holoprosencephaly/ Image via: https://medlineplus.gov/genetics/condition/nonsyndromic-holoprosencephaly/