Alu-specific microhomology-mediated deletions in CDKL5 in females with early-onset seizure disorder.

Mutations in the cyclin-dependent kinase-like 5 (CDKL5) gene in Xp22.13 have been associated with infantile spasms, early-onset intractable epilepsy, and a Rett syndrome (RTT)-like phenotype. Using array comparative genomic hybridization, we identified variable-sized microdeletions involving exons 1-4 of the CDKL5 gene in three females with early-onset seizures. Two of these deletions were flanked by Alu repetitive elements and may have resulted from either non-allelic homologous recombination or the microhomology-mediated Fork Stalling and Template Switching/Microhomology-Mediated Break-Induced Replication mechanism. Our findings demonstrate the first instance of genomic deletion as the molecular basis of CDKL5 deficiency in females and highlight the importance of exon targeted array-CGH analysis for this gene in females with drug-resistant early-onset seizures.

Postoperative airway events of individuals with CHARGE syndrome.

OBJECTIVE: CHARGE syndrome is a heterogeneous genetic disorder comprising multiple congenital anomalies. Major clinical diagnostic criteria include ocular coloboma, choanal atresia/stenosis, characteristic ear abnormalities, and cranial nerve abnormalities. CHARGE syndrome is caused by a mutation in the gene CHD7 located on chromosome 8. Patients with CHARGE syndrome require multiple anesthetics for surgical and otorhinolaryngology procedures. This study describes the postoperative anesthetic related airway events (i.e. re-intubations for apneas and desaturations, airway obstruction due to excessive secretions) of nine individuals with CHARGE syndrome. METHODS: Detailed chart audits were performed on nine patients diagnosed clinically with CHARGE syndrome who had undergone surgery at a single tertiary health centre. The CHARGE characteristics present in each individual, the number and types of surgeries and anesthetics, and the related postoperative airway events were determined. RESULTS: The mean+/-age of the population at chart review was 11.8 years (+/-8.0). The total number of anesthetics was 147, with a mean of 16.2(+/-8.4). Of the 215 surgical procedures (mean 21.9, +/-12.2), 30% were otorhinolaryngological. Postoperative airway events occurred after 35% of anesthetics. Surgeries resulting in the most airway events involved the heart (65%), the gastrointestinal tract (39%), and airway diagnostic scopes, i.e., bronchoscopy, laryngoscopy, and nasopharyngoscopy (36%). Combining multiple surgical procedures under one anesthetic did not increase the risk of postoperative airway events. As individuals aged, they had fewer surgeries and anesthetics, as well as a lower risk of postoperative airway events. CONCLUSION: Individuals with CHARGE syndrome face a significant risk of postoperative airway events with anesthesia, and this is exacerbated by the high number of surgeries they require. Surgeons and anesthesiologists should be aware of potential for postoperative airway events in individuals with CHARGE syndrome and plan accordingly.

Spectrum of CHD7 mutations in 110 individuals with CHARGE syndrome and genotype-phenotype correlation.

CHARGE syndrome is a well-established multiple-malformation syndrome with distinctive consensus diagnostic criteria. Characteristic associated anomalies include ocular coloboma, choanal atresia, cranial nerve defects, distinctive external and inner ear abnormalities, hearing loss, cardiovascular malformations, urogenital anomalies, and growth retardation. Recently, mutations of the chromodomain helicase DNA-binding protein gene CHD7 were reported to be a major cause of CHARGE syndrome. We sequenced the CHD7 gene in 110 individuals who had received the clinical diagnosis of CHARGE syndrome, and we detected mutations in 64 (58%). Mutations were distributed throughout the coding exons and conserved splice sites of CHD7. Of the 64 mutations, 47 (73%) predicted premature truncation of the protein. These included nonsense and frameshift mutations, which most likely lead to haploinsufficiency. Phenotypically, the mutation-positive group was more likely to exhibit cardiovascular malformations (54 of 59 in the mutation-positive group vs. 30 of 42 in the mutation-negative group; P=.014), coloboma of the eye (55 of 62 in the mutation-positive group vs. 30 of 43 in the mutation-negative group; P=.022), and facial asymmetry, often caused by seventh cranial nerve abnormalities (36 of 56 in the mutation-positive group vs. 13 of 39 in the mutation-negative group; P=.004). Mouse embryo whole-mount and section in situ hybridization showed the expression of Chd7 in the outflow tract of the heart, optic vesicle, facio-acoustic preganglion complex, brain, olfactory pit, and mandibular component of the first branchial arch. Microarray gene-expression analysis showed a signature pattern of gene-expression differences that distinguished the individuals with CHARGE syndrome with CHD7 mutation from the controls. We conclude that cardiovascular malformations, coloboma, and facial asymmetry are common findings in CHARGE syndrome caused by CHD7 mutation.

Behavior in CHARGE syndrome: introduction to the special topic.

Challenging behavior in children with CHARGE syndrome has been increasingly a concern of parents, educators, and health professionals. This article introduces the special topic in the American Journal of Medical Genetics on behavior in individuals with CHARGE syndrome. It provides background on CHARGE syndrome, diagnostic criteria, and the relationship of sensory and other physical deficits with both development and behavior. Four themes related to our developing understanding of behavior in CHARGE are described: children with CHARGE have behaviors different from those seen in other syndromes with or without deafblindness. The behavior they display is often very adaptive to their environment and to their own disabilities. These behaviors may be partially related to problems with arousal and self-regulation. And, finally, all papers point to behavior as communication, especially within relationships, where it is essential for maximizing intellectual and social outcomes.