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Assessment of 2q23.1 Microdeletion Syndrome Implicates MBD5 as a Single Causal Locus of Intellectual Disability, Epilepsy, and Autism Spectrum Disorder
Talkowski, M. E. et al. (2011). The American Journal of Human Genetics, 89,551-563.
This article is important due to its large observation group of sixty-five symptomatic individuals. By assessing each chromosome deletion, it is believed MBD5 is the single causal locus for individuals with these groups of symptoms. The paper specifically displays charts comparing individuals with MBD5 specific disruption and that of 2q23.1 deletions. In doing so, it presents a list of numerous characteristic that individuals with this condition may have. It is important to view this list as a sense of potential health risks and to help predict needed therapies and services your child may need in the future. Interestingly, it also discusses the condition overlap with autism spectrum disorders and the need for accurate chromosomal diagnosis.
Neurodevelopmental features in 2q23.1 microdeletion syndrome: Report of a new patient with intractable seizures and review of literature
Motobayashi M. et. al. (2012). American Journal of Medical Genetics Part A. 158A, 4; 861-868.
This article discusses a single patient in detail regarding his neurologic examination findings. Even though varrying intellectual disability is one of the key features for 2q23.1 deletion/duplication disorders, there is not that much literature representing brain changes and development of seizures. Similar to other articles, the author also chooses to compare this patient with 18 other’s described in the literature. It also gives the common findings and the often seen characteristics for this condition.
Haploinsufficiency of MBD5 associated with a syndrome involving microcephaly, intellectual disabilities, severe speech impairment, and seizures
Williams, S. R. et. al. (2010). European Journal of Human Genetics, 18: 436-441; doi: 10.1038/ejhg.2009.199.
This article displays information needed to categorize the common physical characteristics as well as behavioral and intellectual disabilities associated with the disorder. Discussing in detail two individual cases, they are compared to several previously observed individuals with similar deletions. The article shows pictures of the two female subjects to visually display the clinical features associated with the condition.
The 2q23.1 microdeletion syndrome: clinical and behavioural phenotype
van Bon, B. W. M. et. al. (2010). European Journal of Human Genetics, 18:163-170.
In this paper, it describes ten individuals who have 2q23.1 microdeletion syndrome from birth to the time of observation (as old as 26 years). It discusses what conditions may be potentially thought of when initially diagnosing a patient. Importantly, this paper displays a chart that separately lists what characteristics each of the ten cases exhibits. It also shows pictures of each of the ten cases and a graphic display of their genome deletions. As in previously mentioned papers, it also discusses the most common of symptoms and causal genes (MBD5) for producing a symptomatic individual.
2q23.1 microdeletion identified by array comparative genomic hybridisation: an emerging phenotype with Angelman-like phenotype?
Jaillard, S. et. al. (2009). Journal of Medical Genetics. 46: 847-855; doi:10.1136/jmg.2008.058156.
This is a slightly older paper that discusses the observation of two individuals with MBD5 deletions, among other genes. At the time this paper was published, 2q23.1 deletion/duplication syndrome was compared to a previously recognized condition, called Angelman’s Syndrome. This paper is particularly interesting, in its thought process regarding identification of a new condition.
Disruption of an EHMT1-associated chromatin-modification module causes intellectual disability
Kleefstra, T. et. al. (2012). American Journal of Human Genetics. 91, 1; 73-82.
This is one of the most current papers, published just this past July. It is a little more difficult in its reading, but it describes how the MBD5 gene (along with four others), have been found to be associated with intellectual disabilities. It is in this paper that 2q23.1 deletion/duplication disorders are compared with Kleefstra Syndrome Phenotypic Spectrum (with a recognized form of intellectual disability). This paper only looks at a single individual with an MBD5 deletion. It is interesting in the fact, that MBD5 is starting to become a more widely recognized gene associated with intellectual disability, and becoming more popular in current research.
2q23.1 microdeletion of the MBD5 gene in a female with seizures, developmental delay and sitinct dysmorphic features
Noh, G.J. et al. (2011). European Journal of Medical Genetics, doi: 10.1016/j.ejmg.2011.10.001.
This article is one of the first to help identify the critical gene (MBD5) as responsible for its set of distinctive physical and behavioral characteristics. It is consistent with the presence of seizures in 2q23.1 deletion/duplications. The authors observed a single individual to gain information regarding specific facial features and physical/behavioral characteristics which were noted in detail. It discussed the entire medical history of the client. (This aspect is important for all parents to read). The importance of this article lies in the summary of a specific patient and its evidence in support of MBD5 as the critical gene associated with this disease.
2q23.1 De Novo Microdeletion Involving the MBD5 Gene in a Patient With Developmental Delay, Postnatal Microcephaly and Distinct Facial Features
Chung, B. H. Y. et. al. (2010). American Journal of Medical Genetics, Part A, 155: 424-429.
This particular article describes the typical condition features and gene deletion/duplication pattern of a single individual having a 2q23.1 deletion. The article describes the full pregnancy, family and medical history of the client. The findings in the observations and testing were then compared to previously reported individuals with similar deletions. Specifically, this article displays a summary chart giving the range and likelihood of symptoms based on the specific deletion or duplication size etc. Based on these findings, it explains the commonalities of this condition in detail. Because diagnosis for this mutation is still underdeveloped, the seventeen individuals used in summary, it is considered to be a large study population. The importance of this article again, is in its definition of some typically seen symptoms.
2q23.1 Deletion/Duplication Disorders 