Table of Contents
What is Xq28 duplication syndrome?
The int22h1/int22h2-mediated Xq28 duplication syndrome is an X-linked intellectual disability syndrome characterized by variable degrees of cognitive impairment (typically more severe in males), a wide spectrum of neurobehavioral abnormalities, and variable facial dysmorphic features.
Is 22q duplication a disability?
Affected individuals may have intellectual or learning disability, developmental delay, slow growth leading to short stature, and weak muscle tone (hypotonia). Many people with the condition have no apparent physical or intellectual disabilities. It is inherited in an autosomal dominant manner.
How many genes are in Xq28?
The region spans 7.75 megabases of genomic DNA [8] and harbours 105 non-redundant, confirmed protein-coding genes (NCBI Map Viewer [7]). To date, more than 40 diseases have been mapped to Xq28. For 26 of these, the causative genes have been identified.
How common is MECP2?
Frequency. 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.
Does microarray test for Rett syndrome?
Recommended testing strategy High Density SNP Microarray Analysis: Approximately 8% of individuals with classic Rett syndrome and ~3% of those with atypical Rett syndrome are found to have partial or whole MECP2 gene deletions which are NOT identifiable by sequencing3.
What does Microduplication mean?
1 microduplication is a chromosomal change in which a small amount of genetic material on chromosome 1 is abnormally copied (duplicated). The duplication occurs on the long (q) arm of the chromosome at a location designated q21.
What is microdeletion and Microduplication?
Microdeletion and microduplication syndromes are disorders caused by submicroscopic deletions or duplications of contiguous genes on particular parts of chromosomes.
Is 22q a form of Down syndrome?
22q11. 2 deletion is almost as common as Trisomy 21, also known as Down syndrome, which is a more widely recognized chromosomal disorder. Children with 22q11.
Is there a gene for religion?
Until about 25 years ago, scientists assumed that religious behaviour was simply the product of a person’s socialisation – or “nurture”. But more recent studies, including those on adult twins who were raised apart, suggest genes contribute about 40% of the variability in a person’s religiousness.
Is MECP2 genetic?
MECP2 duplication syndrome is caused by a genetic change in which there is an extra copy of the MECP2 gene in each cell. This extra copy of the MECP2 gene is caused by a duplication of genetic material on the long (q) arm of the X chromosome.
What is MECP2 duplication syndrome life expectancy?
The genetic disorder means he will likely start suffering from seizures around the age of five, which will eventually cause his brain to stop functioning normally. The condition was discovered in 2005 and has a life expectancy of about 25 years old.
How is Rett syndrome diagnosed?
The test requires drawing a small amount of blood from a vein in your child’s arm. The blood is then sent to a lab, where the DNA is examined for clues about the cause and severity of the disorder. Testing for changes in the MEPC2 gene confirms the diagnosis.
Can Rett syndrome be detected prenatally?
Prenatal diagnosis for Rett syndrome involves DNA testing to find out whether the developing fetus has a mutation in the MECP2, CDKL5, and FOXG1 genes. Rett syndrome mostly occurs as a result of a de-novo mutation, meaning that the defect is not inherited from the parents but appears spontaneously.
What is int22h1/int22h2-mediated Xq28 duplication syndrome?
The int22h1/int22h2-mediated Xq28 duplication syndrome is a recently recognized X-linked intellectual disability syndrome characterized in males by cognitive impairment, behavioral and psychiatric problems, recurrent infections and atopic diseases, obesity, and distinctive facial features.
Does Xq28 deletion cause intellectual disability?
A mother and daughter from a fourth family were found to carry a heterozygous reciprocal deletion of Xq28 with 100% skewed X-chromosome inactivation of the chromosome with the deletion. Neither had intellectual disability, but the daughter came to attention for hyperactivity, inattentiveness, and sensory integration difficulties.
What is the difference between MECP2 Duplication Syndrome and Xq28 duplication syndrome?
Vandewalle et al. (2009) noted that the duplicated region of chromosome Xq28 harbored by affected individuals did not contain the MECP2 gene ( 300005) and is thus distinct from the duplicated region associated with MECP2 duplication syndrome ( 300260 ). Clinical features also differ.
Where are the Xq28 duplication breakpoints located?
The int22h1/int22h2-mediated Xq28 duplicationbreakpoints are located at the directly oriented LCRs: int22h1 (located within intron22 of F8) and int22h2 (situated ~0.5 Mb telomerically to int22h1). The duplication is mediated by nonallelic homologous recombinationbetween the int22h1 and int22h2 loci [El-Hattab et al 2011].