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What is holoprosencephaly?

Holoprosencephaly is a serious birth defect in which the front part of the brain, known as the forebrain, fails to form correctly.

Normally, during early fetal development the forebrain divides into two halves, creating the left and right hemispheres of the brain.

In babies with holoprosencephaly, this division doesn’t happen as it should, causing malformations of the brain, face and head and neurologic impairment.

Holoprosencephaly is a defect of the central nervous system (CNS). It is sometimes referred to as a cephalic disorder, birth defects of the head caused by problems in the developing fetal nervous system. The condition often occurs with other chromosome abnormalities or genetic syndromes.

Types of Holoprosencephaly

There are three types of holoprosencephaly, based on the severity of the condition:

  • Alobar – the most severe form, when the brain doesn’t divide at all, typically resulting in severe facial abnormalities
  • Semilobar – a somewhat severe form, when the brain's left and right hemispheres are partially but not fully separated
  • Lobar – the least severe form, where the brain is almost completely divided into two halves, with normal or almost normal brain and facial development


In cases involving severe brain malformations, the result is often miscarriage, stillbirth or the baby is unable to survive after birth.

The outlook for babies with holoprosencephaly who survive varies based on the severity of the defect, the child’s symptoms and the presence of other abnormalities.

How does holoprosencephaly affect my baby?

Common complications found in children with holoprosencephaly include:

  • Intellectual disability
  • A small head (microcephaly)
  • Facial defects, including closely set eyes, and cleft lip/palate
  • Seizures/epilepsy
  • Excess fluid in the brain (hydrocephalus)
  • Developmental delays
  • Motor impairment
  • Growth problems
  • Endocrine abnormalities (hormone deficiencies)
  • Pituitary disorders
  • Respiratory problems
  • Gastrointestinal issues and feeding difficulties

Cause and Risk Factors

Holoprosencephaly occurs in an estimated 1 out of every 10,000 births in the United States. The defect is estimated to affect 1 in every 250 pregnancies, but the majority of these pregnancies end in miscarriage.

While the exact cause remains unknown, risk factors include:

  • Chromosomal or genetic abnormalities
  • Family history
  • Environmental factors
  • Maternal diabetes


Holoprosencephaly is typically detected during a routine ultrasound exam. Diagnosis is then confirmed through magnetic resonance imaging (MRI) or a computed tomography (CT) scan.

In mild cases, the condition may not be diagnosed until after birth.

If holoprosencephaly is diagnosed or suspected during pregnancy, you may be referred to a fetal center for a comprehensive evaluation and specialized care. At Texas Children’s Fetal Center, we arrange for a detailed assessment by a team of specialists experienced in the diagnosis of rare fetal brain defects and the care of mother and baby, including maternal-fetal medicine (MFM) physicians, fetal imaging experts, genetic counselors, neonatologists, and pediatric neurologists.

Additional testing may include:

  • High-resolution anatomy ultrasound to confirm the diagnosis, evaluate the defect and identify other abnormalities
  • Ultra-fast MRI for a more detailed view of the fetal brain and any other abnormalities, to determine the severity of the condition
  • Amniocentesis and chromosomal analysis to identify chromosomal anomalies

Following this thorough evaluation, our specialists will meet with you about your results, answer any questions your family has, and discuss your baby’s prognosis.

Pregnancy and Delivery

You and your baby will be closely monitored throughout pregnancy to watch for signs of complications, including the risk of miscarriage.

We recommend delivery at a hospital with the expertise and resources to care for these critically ill newborns, including the highest level of neonatal intensive care (NICU).

Our Fetal Center team works closely with pediatric specialists from Texas Children’s Hospital, consistently ranked one of the best children’s hospitals in the nation by U.S. News & World Report,  ensuring the best possible care for your baby every step of the way.


There is no cure for holoprosencephaly. Treatment is based on the symptoms and needs of each child.

A unique and distinct advantage for mothers delivering at Texas Children’s Pavilion for Women is our location inside one of the largest and most renowned children’s hospitals in the world, for seamless access to the full spectrum of critical care services and specialists your child may need.

For babies with holoprosencephaly, this means no transfers during critical postnatal periods. It also means that the pediatric specialists responsible for treating your child have been an integral part of their care team since before birth.

Postnatal Care Team

Depending on your baby’s symptoms, his or her postnatal care team may include:

Why Texas Children’s Fetal Center?

  • A single location for expert maternal, fetal and pediatric care. At Texas Children’s Hospital, you and your baby receive the specialized care required for the diagnosis and care of holoprosencephaly all in one location, including immediate access to our level IV NICU, the highest level of care available for premature and critically ill newborns.
  • An experienced, compassionate team of specialists. We have a dedicated team of maternal-fetal medicine specialists, neonatologists, fetal imaging experts, pediatric neurosurgeons, and others who work in concert to care for you and your baby every step of the way, using proven protocols we’ve developed over the years. With their combined expertise and unified approach, this remarkable team offers the best possible care for pregnancies and babies with holoprosencephaly.
  • We care for your child’s needs at every stage of life. Our comprehensive approach starts with your first prenatal visit and continues through delivery, postnatal care, and beyond, thanks to one of the nation’s leading teams of fetal and pediatrics specialists for the care and treatment of rare fetal brain defects.

Patient Support Services

Education, advocacy and emotional support are vital to helping families navigate the challenges of a diagnosis of holoprosencephaly.

Our Fetal Center patients benefit from:

Patient Stories

For more information or to schedule an appointment,

call Texas Children’s Fetal Center at 832-822-2229 or 1-877-FetalRx (338-2579) toll-free.

Our phones are answered 24/7. Immediate appointments are often available.