What is holoprosencephaly?

As a baby develops during pregnancy, the upper part of the brain that performs the higher functions usually divides into 2 halves or 2 hemispheres (lobes). In holoprosencephaly the brain grows into one single lobe instead of two.

There are different grades of severity. A baby may have very mild abnormalities and be able to lead a relatively normal life. Or there may be severe abnormalities and limited function. Many babies with the severe form of this disorder die before or soon after birth. Others may live, but may have severely deformed faces and severe cognitive and neurological impairment.

Holoprosencephaly might present as an isolated finding during the ultrasound scan, or it might be part of a wider chromosomal syndrome, such as Trisomys 13, 18, Triploidy or genetic syndrome such as Smith-Lemli-Optiz syndrome or Meckel Gruber syndrome. Your fetal medicine doctor will explain the findings to you in detail and the next steps for your pregnancy care.