Rubinstein-Taybi syndrome (RSTS) is a distinct dominant disorder characterized by short stature, typical face, broad angulated thumbs and halluces, and mental retardation. The RSTS can be caused by chromosomal microdeletions and molecular mutations in the CREBBP gene; however, relatively few mutations have been reported to date. Here, we aimed to determine the rate of point mutations and other small molecular lesions in true RSTS and possible mild variants, by using genomic DNA sequencing. A consecutive series of patients including 17 patients from our previous study was investigated. We identified 19 causative mutations of CREBBP in a total of 45 patients representing three different diagnostic groups: (a) 17 mutations in 30 patients with unequivocal RSTS (detection rate 56.6%), (b) two mutations in eight patients with features suggestive of RSTS ("moderate or incomplete RSTS", detection rate 25%), and (c) no mutation in seven patients with undiagnosed syndromes and isolated features of RSTS. In general, the mutations were distributed without hot spots and most were unique; however, three recurrent mutations (R370X, R1664H, and N1978S) were identified. Furthermore, we detected 15 different intragenic polymorphisms, including two non-synonymous coding polymorphisms, L551I and Q2208H. We report not only the highest detection rate (56.6%) of CREBBP mutations in patients with RSTS to date, but also the second missense mutation (N1978S) in a patient with moderate or incomplete RSTS. Previous studies have identified cytogenetic deletions in the CREBBP gene in eight to 12% of patients and very recently, Roelfsema et al. reported EP300 gene mutations in three of 92 (3.3%) patients with either true RSTS or different syndromes resembling RSTS. Our 56.6% detection rate of molecular mutations in CREBBP in patients with unequivocal RSTS supports the new concept that RSTS is a genetically heterogeneous disorder and furthermore, indicates that RSTS may be caused by gene/s other than CREBBP in up to 30% of cases.

Supernumerary marker chromosomes (SMCs) are frequently found at pre-and postnatal cytogenetic diagnosis and require identification. A disproportionally large subset of SMCs is derived from the human chromosome 22 and confers tri-or tetrasomy for the cat eye chromosomal region (CECR, the proximal 2 Mb of chromosome 22q) and/or other segments of 22q. Using fluorescence in situ hybridization (FISH) and 15 different DNA probes, we studied nine unrelated patients with an SMC(22) that contained the CECR. Five patients showed the small (type I) cat eye syndrome (CES) chromosome and each one had the larger (type II) CES chromosome, small ring chromosome 22, der(22)t(11;22) extrachromosome, and a novel type of bisatellited SMC (22) with breakpoints outside the low-copy repeats (LCRs22). By size and morphology, the novel bisatellited SMC(22) resembled the typical (types I and II) CES chromosomes, but it might have been associated with the chromosome 22q duplication syndrome, not CES. This SMC included a marker from band 22q12.3 and conferred only one extra copy each of the 22 centromere, CECR, and common 22q11 deletion area. There has been no previous report of a bisatellited SMC(22) predicting the chromosome 22q duplication syndrome. Accounting for the cytogenetic resemblance to CES chromosomes but different makeup and prognosis, we propose naming this an atypical (type III) CES chromosome. In this study, we found six distinct intervals on 22q to be relevant for FISH diagnostics. We propose to characterize SMCs(22) using DNA probes corresponding to these intervals.

Rubinstein-Taybi syndrome (RSTS) is a well-known autosomal dominant mental retardation syndrome with typical facial and skeletal abnormalities. Previously, we have reported two patients presenting with RSTS and additional clinical features including failure to thrive, seizures, and intractable infections (Bartsch et al. in Eur J Hum Genet 7:748-756, 1999). Recently we identified a third patient with this condition, termed here severe RSTS, or chromosome 16p13.3 deletion syndrome. The three patients died in infancy, and all displayed a specific mutation, a chromosomal microdeletion including the 3'-end of the CREBBP gene. Using fluorescence in situ hybridization and closely spaced DNA probes, we characterized the deletion intervals in these patients and in three individuals with a deletion of CREBBP and typical RSTS. The deleted DNA segments were found to greatly vary in size, spanning from approximately 40 kb to >3 Mb. Four individuals, including the patients with severe RSTS, exhibited deletions containing gene/s in addition to CREBBP. The patients with severe RSTS all had deletions comprising telomeric neighbor genes of CREBBP, including DNASE1, a dominant gene encoding a nuclease that has been associated with systemic lupus erythematodes. Our findings suggest that severe RSTS is distinct from RSTS and represents a novel true contiguous gene syndrome (chromosome 16p13.3 deletion syndrome). Because of the risk of critical infections and high mortality rate, we recommend that the size of the deletion interval should be determined in CREBBP deletion-positive patients with RSTS, especially in young children. Further studies are needed to delineate the clinical spectrum of the new disorder and to clarify the role of DNASE1.

Background: Research has demonstrated lower access to healthcare services by immigrant patients in comparison to native people. Cultural and linguistic differences have been considered as main factors that impede this access and as barriers to creating an effective relationship between immigrant patients and health professionals.  Objective: The aim of this study was to better understand and synthesize the available evidence regarding the impact of immigrant patients’ language proficiency on access to health care. Methods: A systematic literature search was performed to identify studies published between January 2000 and January 2019 that examined the impact of language proficiency on access to and use of health services by immigrant patients. Only articles in English were included. Cross-referencing of the identified articles was also performed.  Results: A total of 140 publications was identified through online databases. In all 24 studies were reviewed, and the results were reported using four interrelated themes identified from the articles. These reports consistently showed a clear association between inadequate language ability and underuse of health care services, ineffective communication, and increased use of emergency care by immigrant patients. Identifying factors that can influence access to care, applying immigrant-friendly solutions such as provision of professional interpreters, and encouraging culturally and linguistically sensitive education may improve the quality of care and increase access to care. One study recommended utilisation of communication technologies such as telemedicine to bridge the communication gap and increase accessibility of healthcare services by immigrant patients.  Conclusions: All included studies indicated that language barriers hindered access to healthcare services. The data resulting from this study can update policy and practical solutions for language barriers on access to care by immigrant patients and provide an agenda for further investigations.

Purpose Preimplantation Genetic Diagnosis (PGD) has proven to be a useful reproductive option for carriers of some chromosome rearrangements. The data presented in this study compares the impact of one versus two blastomere biopsy on the likelihood of achieving a PGD result, as well as the effect on subsequent embryo development and clinical outcomes. Methods IVF-PGD couples had either one or two blastomeres biopsied from all embryos with ≥7 blastomeres on day 3 post oocyte collection. These blastomeres were assessed for the specific chromosome rearrangement using Fluorescent In-situ Hybridisation (FISH). Further embryo development was monitored on days 4 and 5. Clinical outcomes were assessed retrospectively. Results The data shows that statistically more embryos achieved a PGD result following two blastomere biopsy, compared with one blastomere biopsy (92 % versus 88 %, respectively). Furthermore it was found that embryo development and clinical outcomes were similar between the two biopsy groups. Conclusions Based on this analysis it appears that the biopsy of two blastomeres from embryos with ≥7 blastomeres on day 3 is a valid and successful approach for couples presenting for IVF-PGD for a chromosome rearrangement.