Importance of early diagnosis of Stickler syndrome in newborns

Objective: The study aims to investigate a possible correlation between the main clinical and ophthalmological characteristics, age and Robin sequence in patients with the Stickler syndrome. Introduction: The Stickler syndrome is an autosomal dominant genetic disorder, characterised by ocular, orofacial and skeletal anomalies and/or auditory loss. Patients with Robin sequence features and respiratory complications are frequently diagnosed with the Stickler syndrome. The heterogeneous phenotypic manifestations may present a challenge for early clinical diagnosis. Methods: We performed a retrospective study of the 98 patients with the Stickler syndrome, between November 1995 and June 2009. The data were compared to investigate their ocular alterations and association with the Robin sequence. To be included, patients had to present with the following triad: cleft palate, facial features (hypoplastic midface, micrognathia and prominent eyes) and ocular anomalies (myopia and/or abnormalities of the retina). Results: Fifty-one percent of the patients presenting with Robin sequence features had been diagnosed with the Stickler syndrome. Ocular alterations were found in 50% of the patients. Discussion: The Robin sequence may appear as an isolated condition or associated with other features, or else as part of other known syndromes. Currently, the diagnosis of the Stickler syndrome is based on clinical signs. Affected individuals eventually develop hearing loss, retinal detachment and blindness. The ophthalmological complications associated are usually progressive and can lead to blindness.

Regulatory variation in a TBX5 enhancer leads to isolated congenital heart disease

Recent studies have identified the genetic underpinnings of a growing number of diseases through targeted exome sequencing. However, this strategy ignores the large component of the genome that does not code for proteins, but is nonetheless biologically functional. To address the possible involvement of regulatory variation in congenital heart diseases (CHDs), we searched for regulatory mutations impacting the activity of TBX5, a dosage-dependent transcription factor with well-defined roles in the heart and limb development that has been associated with the HoltOram syndrome (hearthand syndrome), a condition that affects 1/100 000 newborns. Using a combination of genomics, bioinformatics and mouse genetic engineering, we scanned approximate to 700 kb of the TBX5 locus in search of cis-regulatory elements. We uncovered three enhancers that collectively recapitulate the endogenous expression pattern of TBX5 in the developing heart. We re-sequenced these enhancer elements in a cohort of non-syndromic patients with isolated atrial and/or ventricular septal defects, the predominant cardiac defects of the HoltOram syndrome, and identified a patient with a homozygous mutation in an enhancer approximate to 90 kb downstream of TBX5. Notably, we demonstrate that this single-base-pair mutation abrogates the ability of the enhancer to drive expression within the heart in vivo using both mouse and zebrafish transgenic models. Given the population-wide frequency of this variant, we estimate that 1/100 000 individuals would be homozygous for this variant, highlighting that a significant number of CHD associated with TBX5 dysfunction might arise from non-coding mutations in TBX5 heart enhancers, effectively decoupling the heart and hand phenotypes of the HoltOram syndrome.

'Synthetic lipase' production from a newly isolated Sporidiobolus pararoseus strain by submerged fermentation

The lipase produced by a newly isolate Sporidiobolus pararoseus strain has potential catalysis ability for esterification reactions. In order to improve its synthetic activity, this work aimed at optimizing 'synthetic lipase' production by submerged fermentation of a conventional media based on peptone, yeast extract, NaCl and olive oil using experimental design technique. According to the results obtained in the first experimental design (2(4-1)), yeast extract and NaCl concentrations were tested to further optimization by response surface methodology. The maximum 'synthetic lipase' activity obtained was 26.9 U/mL in the optimized media (5.0, 6.8, 7.0 and 1.0% (wt/v) of peptone, yeast extract, NaCl and olive oil, respectively), representing a 6.36-fold increase compared to the initial medium. The time course of 'synthetic lipase' production in the optimized condition was evaluated in terms of synthetic activity, protease activity, biomass and total carbon and the maximum synthetic activity was observed during the stationary phase of growth.