What is chromosome 7q11 23?
7q11. 23 duplication syndrome results from an extra copy of a region on the long (q) arm of chromosome 7 in each cell. This region is called the Williams-Beuren syndrome critical region (WBSCR) because its deletion causes a different disorder called Williams syndrome, also known as Williams-Beuren syndrome.
Can Williams syndrome be passed on?
Most cases of Williams syndrome are not inherited but occur as random events during the formation of reproductive cells (eggs or sperm) in a parent of an affected individual. These cases occur in people with no history of the disorder in their family.
How is 7q11 23 duplication diagnosed?
Diagnosis/testing. The diagnosis of 7q11. 23 duplication syndrome is established by detection of a recurrent 1.5- to 1.8-Mb heterozygous duplication of the Williams-Beuren syndrome critical region.
How often does MECP2 duplication syndrome occur?
The prevalence of MECP2 duplication syndrome is unknown; more than 200 affected individuals have been described in the scientific literature. It is estimated that this condition is responsible for 1 to 2 percent of all cases of intellectual disability caused by changes in the X chromosome.
What are the symptoms of duplication?
What are the signs and symptoms of MECP2 duplication syndrome?
- Hypotonia (low muscle tone), which is usually apparent in infancy.
- Delayed development of milestones.
- Moderate to severe intellectual disability.
- Inability to talk, or limited speech ability that may be lost with age.
What is it like to have Williams syndrome?
Newborns with Williams syndrome have characteristic “elfin-like” facial features including an unusually small head (microcephaly), full cheeks, an abnormally broad forehead, puffiness around the eyes and lips, a depressed nasal bridge, broad nose, and/or an unusually wide and prominent open mouth.
What disease does Duplication cause?
MECP2 duplication syndrome is a severe neurological and developmental disorder. Signs and symptoms include low muscle tone ( hypotonia ) in infancy, developmental delay , severe intellectual disability , and progressive spasticity . Other signs and symptoms may include recurrent respiratory infections and seizures .
Can duplication syndrome be inherited?
In most cases, MECP2 duplication syndrome is inherited from a mother who carries the duplication but has no symptoms. Rarely, the condition is not inherited. In these cases it may occur randomly during the formation of the egg or sperm, or shortly after the egg and sperm join together.
How is duplication syndrome diagnosed?
Clinical Testing and Workup There are a variety of tests that can be used to diagnose MECP2 duplication syndrome including array comparative genomic hybridization (array-CGH). This test can detect the gain or loss of chromosomal material including microduplications.
Do people with Williams syndrome have perfect pitch?
Additionally, recent research suggests that the percentage of individuals with Williams syndrome who have perfect pitch is higher than the percentage among individuals in the general population.
