Miller-Dieker syndrome is a condition characterized by a pattern of abnormal brain development known as
Most children pass away by the age of 2, while some live to age 10. It's rare for a child to survive into their teen years.
Miller-Dieker syndrome is caused by a deletion of genetic material near the end of the short (p) arm of chromosome 17. The signs and symptoms of Miller-Dieker syndrome are probably related to the loss of multiple genes in this region. The size of the deletion varies among affected individuals.
Miller-Dieker syndrome (MDS) is a genetic condition characterized by a specific brain malformation (lissencephaly); distinctive facial features; and severe neurologic abnormalities including intellectual disability and seizures. Very few affected children survive beyond childhood.
The life expectancy of lissencephaly is generally short. Many children with the condition die before they reach 10 years of age. The most common cause of death among people with lissencephaly is aspiration (breathing in a foreign object, such as sucking food into your airway) and respiratory disease.
Children with isolated lissencephaly may sit or roll, and rare patients with mild agyria and pachygyria will walk. Nevertheless, a majority of patients show no significant development beyond the 5-month level.
There is no cure for lissencephaly, but some people can improve over time. Doctors and parents focus on controlling and addressing the symptoms. Physical, occupational, and speech therapy could help in some cases. People living with the condition might need medications to control seizures.
This genetic form of lissencephaly can be observed in more than one child per family, because the mutation can be present in the DNA of a healthy mother.
Lissencephaly is caused by defective neuronal migration during embryonic development, the process through which nerve cells move from their place of origin to a permanent location within cerebral cortex gray matter.
Lissencephaly is a rare genetic brain condition. It causes the brain's outer layer to appear smooth. Other symptoms include slow cognitive development, intellectual disability, an abnormally small head, muscle spasms, seizures, and deformed hands, fingers, and toes.
Brain malformation syndromes.
Miller–Dieker syndrome is characterized by severe lissencephaly (“smooth brain” with agyria), severe developmental impairment, hypotonia early in life, and hypertonia with age. The facial changes include bitemporal hollowing, upturned nares, thin vermilion border, and small jaw.
Eyes are widely spaced with upward slanting fissures. The nose is very short with anteverted nares. The upper lip is long, wide, and thick. The ears may have minor flattening of the helices.
Diagnosis. The diagnosis of lissencephaly is often not made until a child is a few months old, and many children with the condition appear healthy at the time of delivery. Parents usually note that their child isn't developing at a normal rate around the age of 2 to 6 months.
MDS was named for the two physicians, James Q. Miller and H. Dieker., who independently described the condition in the 1960s. The hallmark of MDS is lissencephaly, a condition in which the outer layer of the brain, the cerebral cortex, is abnormally thick and lacks the normal convolutions (gyri).
Koalas, like many other primitive animals, have a smooth (or lissencephalic) brain, meaning that their brains have no folds! This is why koalas are often unable to perform complex behaviours. Koalas are known for being sleepy and lazy, which is likely due to a nutrition-poor diet of otherwise toxic eucalyptus leaves.
Inheritance. The inheritance pattern of ILS depends on the gene involved. When ILS is caused by mutations in the PAFAH1B1 or TUBA1A gene, it is inherited in an autosomal dominant pattern , which means one copy of the altered gene in each cell is sufficient to cause the disorder.
It is possible to detect fetal lissencephaly between 20- and 24-week gestational age; but, it is considerably easier in the third trimester.
Lissencephaly, an absence or reduction of cerebral gyri, is a rare disorder seen in Lhasa Apsos, Pekingese, and Australian Kelpies. It is also seen in association with cerebellar hypoplasia in Irish Setters, Wirehaired Fox Terriers, and Samoyeds and in Korat cats with microencephaly.
Since there is a wide spectrum of cerebral involvement in lissencephaly, only severe forms of lissencephaly can be detected on prenatal ultrasound; milder degrees of cerebral involvement such as pachygyria and subcortical band heterotopia are difficult to diagnose.
It is to consider lissencephaly in the diagnosis of developmental delay with seizure disorder as many patients may be diagnosed as cerebral palsy. Several lissencephaly syndrome have been described, Here three cases of lissencephaly with developmental delay and Intractable seizures are reported.
Affecting just one in 100,000 children, lissencephaly (sometimes known by its literal translation as “smooth brain”) is typically caused by a chromosomal deletion in a baby that occurs during a woman's pregnancy and prevents the brain from developing normally.
Postnatal diagnosis
Caution is however required while dealing with the results as misdiagnosis is possible due to the similarity of the signs displayed by polymicrogyria and lissencephaly.
Lissencephaly type II is characterized by reduction in normal sulcation, associated with a bumpy or pebbly cortical surface (thus the term cobblestone lissencephaly), absent in lissencephaly type I. Unlike type I lissencephaly which is the result of neuronal undermigration, type II is due to overmigration.
Lissencephaly is a group of disorders that is characterized by an abnormally smooth surface of the cerebral cortex. It has generally been divided into two categories: classic lissencephaly (also known as type 1 lissencephaly) and cobblestone complex (also known as type 2 lissencephaly).
Disease at a Glance
Additional symptoms and findings typically include severe or profound intellectual disability, seizures, abnormally increased muscle tone (hypertonia), exaggerated reflexes (hyperreflexia), and severe growth failure. This condition is inherited in an autosomal recessive fashion.