What causes holoprosencephaly?
What causes holoprosencephaly?
The most common chromosomal abnormality associated with HPE is when there are 3 copies of chromosome 13 (trisomy 13), although a number of other chromosomal changes can also cause holoprosencephaly. In other children, holoprosencephaly is due to a change in a specific gene.
What happens in the body to cause holoprosencephaly?
Holoprosencephaly occurs when the brain fails to divide properly into the right and left hemispheres. This condition is called nonsyndromic to distinguish it from other types of holoprosencephaly caused by genetic syndromes, chromosome abnormalities, or substances that cause birth defects (teratogens).
How does holoprosencephaly affect the body?
Holoprosencephaly (HPE), pronounced “hah-low-prah-sen-SEH-fuh-lee,” is a birth defect (congenital condition) that causes a developing baby’s brain to not properly separate into the right and left hemispheres (halves). HPE can also affect the development of an unborn baby’s head and face.
How does Alobar holoprosencephaly occur?
Alobar holoprosencephaly is when there is a complete failure of the brain to divide into right and left hemispheres which results in the loss of midline structures of the brain and face as well as fusion of the cavities of the brain, known as lateral ventricles and the third ventricle (which are normally separated).
What is holoprosencephaly Alobar?
Holoprosencephaly is an abnormality of brain development in which the brain doesn’t properly divide into the right and left hemispheres. The condition can also affect development of the head and face. There are 4 types of Holoprosencephaly, distinguished by severity.
How common is Alobar holoprosencephaly?
There are three types of HPE: alobar being the most severe form, semilobar being intermediate and lobar being the least severe form. Holoprosencephaly is the most common forebrain defect and can be as common as 1 in every 250 embroys and 1 in every 10,000 newborns.
What causes HPE disease?
The most common known cause of HPE in humans is maternal type 2 diabetes mellitus. In pregnancies of diabetic mothers, the chance for HPE to occur is about 1%. Approximately 25%-50% of individuals with HPE have a chromosome error as the underlying cause of their HPE.
How is Alobar holoprosencephaly diagnosed?
Prenatal ultrasound of the face and falx cerebri can be used to diagnose alobar and semilobar holoprosencephaly as early as the first trimester [10,33], while fetal MRI provides more sensitive diagnosis for milder forms of holoprosencephaly during the third trimester [35].
What are some interesting facts about holoprosencephaly?
In most cases of holoprosencephaly, the malformations are so severe that babies die before birth. In less severe cases, babies are born with normal or near-normal brain development and facial deformities that may affect the eyes, nose, and upper lip.