Miller-Dieker lissencephaly syndrome
What is Miller-Dieker lissencephaly syndrome?
Miller-Dieker lissencephaly syndrome is a genetic condition identified by a pattern of abnormal brain development known. This is known in medical terms as lissencephaly. The normal brain has many folds and grooves and individuals with Miller-Dieker lissencephaly syndrome have fewer folds and grooves or what looks like an abnormally smooth brain. Because of this condition, individuals have severe intellectual disability, seizures, developmental delay, a floppy baby appearance that is called hypotonia, as well as abnormal muscle stiffness. Feed difficulties are also problematic. For many, the less folds and grooves found in the brain, the more severe the associated symptoms are.
In addition to fewer folds and grooves found in the brain, those with lissencephaly Miller-Dieker syndrome tend to display distinctive facial features such as a prominent forehead; a sunken appearance seen in the middle of the face; a small, upturned nose; low-set and abnormally shaped ears; a small jaw; and a thick upper lip.
Rarely, affected individuals will have heart or kidney problems. Also rare, but having been reported, is an opening in the wall of the abdomen, The medical term for this is an omphalocele, which allows the abdominal organs to protrude through the belly button. Unfortunately, individuals with Miller-Dieker syndrome do not survive beyond childhood.
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What are the usual abbreviations for Miller-Dieker lissencephaly syndrome?
The usual abbreviations for Miller-Dieker lissencephaly syndrome are MDLS and MDS.
Are there other names for Miller-Dieker lissencephaly syndrome?
There are other names for Miller-Dieker lissencephaly syndrome. They are the following:
• Chromosome 17p13.3 deletion syndrome
• LIS1-associated lissencephaly
If you have questions about whether an abbreviation or name of condition is similar to Miller-Dieker syndrome, ask your main doctor or genetics doctor.
What do “p” and “13.3” stand for in chromosome 17p13.3 deletion syndrome?
All of our genetic information is held in packages called chromosomes. Every chromosome has two arms. These are named the “p” arm and the “q” arm. The “p” arm is the short arm (p comes from the French word petit meaning small) and typically shown as the top of the chromosome. The “q” arm is the long arm and typically shown as the bottom of the chromosome. The “p” and “q” arms are separated by something called the centromere, the center area between the two arms of the chromosome. The number “13.3” is the specific place on the short arm of chromosome 17 where the missing piece (deletion) is located. Knowing where a specific deletion of genetic material is located helps the genetics doctor to understand what features a person may develop.
The best person to explain chromosomes and what it means to have a missing piece of genetic material is a genetics doctor or a genetic counselor. To find a genetic counselor in a specific location, use the Find a Genetic counselor tool through the National Society of Genetic Counselors.
How common is Miller-Dieker lissencephaly syndrome?
The exact prevalence of Miller-Dieker lissencephaly syndrome is unknown, but it is thought to be a rare condition. The specific brain difference called lissencephaly (smooth brain) is thought to be seen in 11.7-40 per million birth. This number may not capture all people who have this type of brain difference.
Are any other genetic conditions similar to Miller-Dieker lissencephaly syndrome?
There are other genetic conditions that include lissencephaly (smooth brain). Similar conditions to Miller-Dieker lissencephaly syndrome include:
- LIS1-related malformations. Classic lissencephaly is caused by mutations in the LIS1 gene.
- DCX-¬related malformations. Classic lissencephaly is caused by mutations in the DCX gene.
- TUBA1A-related malformations. Classic lissencephaly is caused by mutations in the TUBA1A gene. Mutations in this gene can also cause a small and underdeveloped cerebellum (Norman-Roberts syndromes).
- Baraitser-Winter syndrome. Features include lissencephaly, a characteristic head shape, and eye malformations (shallow orbits, droopy eyelids, holes in the iris, choroid, or both).
- Walker-Warburg syndrome. Features include “cobblestone” lissencephaly, severe developmental delay and intellectual disability, muscle weakness and wasting early in life, and eye abnormalities.