Development of a Low Cost Semiquantitative Polymerase Chain Reaction Assay for Molecular Diagnosis of Williams Syndrome.

BACKGROUND: Williams Beuren Syndrome (WBS) is a well-recognized and common genetic cause of congenital heart defects, developmental delay, hypercalcemia, and characteristic facial features. It is caused by a 1.5 - 1.8 Mb heterozygous deletion of chromosome 7q11.23 with loss of around 28 coding genes. The aim of this study was to develop a low-cost, semi-quantitative PCR (sqPCR) method to detect the chromosome 7q11.23 deletion. METHODS: Twenty-four suspected WBS cases were recruited following ethical clearance and informed consent. Blood was obtained, DNA extracted and spectrophotometrically quantified using standard methods. To detect the deletion by dosage analysis, a target region within a gene located in the WBS commonly deleted region of 7q11.23 was amplified together with a control region in a duplex sqPCR assay. The control region was telomeric to the WBS commonly deleted region and was located in chromosome 7q31.2. The two target regions within the deleted region namely a locus within ELN and a marker in the intergenic region between FZD9 and FKBP6 and designated IFF, were amplified in separate duplex sqPCR assays. The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene was used as the control for normalization. Included in the assay were a non-deleted and deleted individuals' samples. RESULTS: Nineteen patients were identified to have the deletion while five did not. All 24 patients' results were confirmed by whole exome sequencing and 11 also by fluorescence in-situ hybridization (FISH). CONCLUSIONS: The data obtained indicates the sqPCR assay developed in this study to be an accurate and reliable diagnostic test for WBS. Most Sri Lankan patients with WBS are diagnosed clinically, as many parents of affected WBS children are unable to afford currently available molecular diagnostic testing. This low cost sqPCR test is therefore likely to benefit Sri Lankan WBS patients, by enabling genetic testing for confirming or refuting a clinical diagnosis of WBS and may be of use in other low and middle income countries.

Hybrid strategies for high-risk non-hypoplastic left heart syndrome patients.

Single-stage repair of complex cardiac abnormalities in high-risk neonates presents formidable challenges. The majority of hybrid strategies involving bilateral pulmonary artery banding (bPAB) with or without patent ductus arteriosus (PDA) stenting is described in the setting of hypoplastic left heart syndrome. We present a series of cases describing two-stage repair with initial palliative hybrid procedures involving bPAB with or without PDA stenting. This allows weight gain and stabilization of circulation before complete repair, provides good results, and may overcome risk factors associated with single-stage repair in neonates.

Moore's law, Dabbawalas, and pediatric cardiac care in Sri Lanka.

Sri Lanka is an island nation in Indian Ocean that provides free healthcare to all citizens through government healthcare system. It has commendable health indices in the region. Pediatric cardiac services have rapidly progressed over past few years helping to further bring down infant and under-five mortality rates. Lady Ridgeway Hospital for Children (LRH) is the only tertiary care referral center for children with heart disease in the country. Currently it performs approximately 1,000 cardiac catheterizations and 1,000 cardiac surgeries every year. Target is to double the surgical output to treat all children with heart diseases in a timely and appropriate manner. Being a middle-income country, this is not an easy task. Technology used in diagnosis and treatment of congenital heart diseases is rapidly advancing with its price tag. In such a setting, it is challenging to proceed to achieve this target in a resource-limited environment.