Miller Dieker Syndrome

What is Miller Dieker Syndrome?

Miller Dieker Syndrome (MDS) is a resultant of genetic depletion occurs in the chromosome 17p13.3 adjacent gene. The classic feature of MDS is lissencephaly (a specific brain malformation along with distinct facial features.

Congenital defects are also present in most of the cases, which may vary from one to another. Both hereditary and inheriting risk are there for the development of the Miller-Dieker syndrome.

The exact prevalence of Miller-Dieker syndrome is unknown, but it is considered as a rare genetic disorder^1,2

Genetic Alteration

In Miller-Dieker syndrome, the short arm (p) of the chromosome 17 and the associated genetic material is depleted. The Miller-Dieker Syndrome symptoms are resultant of the loss of several genes in the particular region.

The extent of chromosomal depletion varies from patient to patient. It has been identified by the researchers that depletion of PAFAH1B1 gene on chromosome 17 is responsible for the onset of lissencephaly in Miller-Dieker Syndrome.

The deletion of YWHAE gene in a particular region of chromosome 17 is even responsible for the severity of the lissencephaly in people with Miller-Dieker syndrome. Perhaps the additional loss of genes in that particular region involved in chromosome 17 is accountable for associated features of Miller-Dieker syndrome^2.

Symptoms

The primary symptoms associated with Miller-Dieker syndrome (MDS) is lissencephaly, which is a resultant of abnormal brain development and responsible for various neurological problems and distinctive facial features. In addition, some congenital disorders may also present. The included sign and symptoms are as follows:

• Delayed development occurs in both physically and mentally. Most of the affected children unable to learn how to sit and walk in their early life.
• Disable intellectuality
• Difficulty in feeding and swallowing
• Hypotonia (low muscle tone)
• Seizures attacks started before six months of age
• Smaller head size (microcephaly)
• Growth Retardation
• The severity of the symptoms varies from patient to patient depending on the severity of the brain abnormality.
• The symptoms related to distinctive facial features are as follows:
• An elevated forehead
• Midface hypoplasia (the middle part of the face is appeared as depressed)
• Anteverted nares with a depressed nasal route and tiny nose
• Compacted ear helices and low-set
• Micrognathia (a small jaw)
• Small chin
• The upper lip boarder is vermillion with a downward facing

In addition to the above-mentioned symptoms, kidney and the cardiac problem also associated with some of the Miller Dieker Syndrome affected the individual. Some other organ specific abnormalities are omphalocele (the wall of the abdomen has an opening); contractures rigidity of the joint); clinodactyly (curved finger)^1,2,3.

Diagnosis

Different radiological imaging tools are applied to diagnose the Miller Dieker Syndrome. MTI and CT scan of the brain are primary diagnostic tool applied to detect the brain abnormality. Apart from these, genetic testing is important to detect the genetic involvement.

Other diagnostic tests depend on the patient’s symptoms and severity of the condition, which include X-ray, ultrasonography etc⁴.

Treatment

There is no specific treatment available for Miller Dieker Syndrome. Doctors usually prescribed anti-epileptic drugs for controlling seizure attacks in patients with Miller–Dieker syndrome. In addition, supportive therapy is required in the management of Miller Dieker Syndrome affected patients⁵.

Prognosis

The prognosis of the Miller Dieker Syndrome is poor. The survival rate of this condition depends on the severity of the lissencephaly. In most of the cases, the patient died due to aspiration pneumonia, which is resultant of poorly controlled airways.

The delayed development is a classic feature of Miller Dieker Syndrome and the degree of severity varies with the extent of brain malformation. The symptoms related to delayed development is commencing at the age of 3 to 5 months along with seizure attacks. Uncontrolled seizure attacks cause more severe developmental abnormalities¹.

Life Expectancy

Miller Dieker Syndrome affected individuals usually not survive beyond their childhood. very rarely some of them can cross their childhood. Most of the Miller-Dieker syndrome affected children die at the years of age and that can be extent until 10 years of age in very few patients. Yet now medically documented report showed maximum life expectancy occur at 17 years of age¹.

References

1. Miller-Dieker syndrome; Genetic and Rare Diseases Information Center; Retrieve from https://rarediseases.info.nih.gov/diseases/3669/miller-dieker-syndrome
2. Miller-Dieker syndrome; Genetic Home Reference; Retrieve from https://ghr.nlm.nih.gov/condition/miller-dieker-syndrome#diagnosis
3. Dr. Daniela Pilz, (2003). Miller-Dieker Syndrome. Orphanet. https://www.orpha.net/data/patho/GB/uk-MDS.pdf
4. Radswiki et al. Miller-Dieker syndrome. Radiopaedia; Retrieve from https://radiopaedia.org/articles/miller-dieker-syndrome-1
5. T E Herman, M J Siegel. Miller–Dieker syndrome, type 1 lissencephaly. Journal of Perinatology (2008) 28, 313–315; doi:10.1038/sj.jp.7211920. Retrieve from
6. http://www.nature.com/jp/journal/v28/n4/full/7211920a.html