What is Moebius syndrome caused by?
Moebius syndrome is a rare birth defect caused by the absence or underdevelopment of the 6th and 7th cranial nerves, which control eye movements and facial expression. Many of the other cranial nerves may also be affected, including the 3rd, 5th, 8th, 9th, 11th and 12th.
Is Moebius syndrome autosomal recessive?
In familial cases, there is evidence that Moebius syndrome is inherited as an autosomal dominant trait. Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease.
What chromosome does Moebius syndrome affect?
The disorder appears to be associated with changes in particular regions of chromosomes 3, 10, or 13 in some families. Certain medications taken during pregnancy and abuse of drugs such as cocaine may also be risk factors for Moebius syndrome.
What is the lifespan of someone with Moebius syndrome?
With continued proper medical care, individuals with Moebius , who do not have serious life threatening complications in their first year of life, usually have a normal life expectancy.
What is the 7th facial nerve?
The facial nerve is the 7th cranial nerve and carries nerve fibers that control facial movement and expression. The facial nerve also carries nerves that are involved in taste to the anterior 2/3 of the tongue and producing tears (lacrimal gland). Facial Paralysis and Facial Reanimation.
How is Moebius syndrome related to genetics and inheritance?
Genetics and Inheritance of Moebius Syndrome. Mutations of the genes PLXND1 and REV3L have also been pinpointed as being associated with Moebius syndrome, based on animal studies showing nerve deficits typical of the syndrome when mutations of those genes are introduced in animals.
Are there any other names for Moebius syndrome?
Other Names: Mobius syndrome; Congenital facial diplegia; Congenital facial diplegia syndrome; Mobius syndrome; Congenital facial diplegia; Congenital facial diplegia syndrome; Congenital oculofacial paralysis; Moebius sequence; MBS; Absence or underdevelopment of the 6th and 7th cranial nerves See More.
What causes muscle weakness and paralysis in Moebius syndrome?
Abnormal development of cranial nerves leads to the facial muscle weakness or paralysis that is characteristic of Moebius syndrome. Researchers speculate that Moebius syndrome may result from changes in blood flow to the brainstem during early stages of embryonic development.
How does Moebius syndrome affect your eye movement?
Moebius syndrome also affects muscles that control back-and-forth eye movement. Affected individuals must move their head from side to side to read or follow the movement of objects. People with this disorder have difficulty making eye contact, and their eyes may not look in the same direction (strabismus).
What kind of mutations are associated with Moebius syndrome?
Mutations of the genes PLXND1 and REV3L have also been pinpointed as being associated with Moebius syndrome, based on animal studies showing nerve deficits typical of the syndrome when mutations of those genes are introduced in animals.
How to tell if you have Moebius syndrome?
Both criteria must be present for a diagnosis of Moebius syndrome. These two symptoms may be due to impairment in the facial nerve (cranial nerve 7) and the abducens nerve (cranial nerve 6), respectively. In addition to the above strict clinical criteria, additional signs or symptoms may also be present, including, but not limited to:
What kind of palsy does Moebius syndrome cause?
Moebius syndrome is a type of congenital facial paralysis or palsy. The condition usually affects both sides of the face. While researchers have not identified the cause (s) of Moebius syndrome, studies suggest a combination of genetic and environmental risk factors.
How is PLXND1 related to Moebius syndrome?
PLXND1 is connected to neural migration during hindbrain development and REV3L plays a role in DNA translesion synthesis, a process which repairs damaged DNA. PLXND1 has been mapped to chromosome 3q22.1. A novel mutation of PLXND1 was found in a patient diagnosed with Moebius syndrome in 2015.