A Review of Next‐Generation Genetic Testing for the Dermatologist

Dermatologists have been placed in a prime position to make new genetic discoveries. Tissue is easily obtained from the skin or mucosa for the study of germline and somatic mosaic disorders. This, along with the recent development of next‐generation sequencing, makes dermatology an exciting field with essentially endless possibilities for discovering genes responsible for disease, better understanding complex molecular pathways, and eventually developing targeted therapies. To take advantage of this great opportunity, a basic understanding of the advances in genetic testing is vital. Herein we give an overview of next‐generation sequencing, including some of the applications it may be used for. We also review various study designs for genetic discovery, each of their benefits and downfalls, and how they may be applied to the study of dermatologic disease.     

Retrospective diagnosis of chondrodysplasia punctata

The diagnosis of punctate epiphyseal dysplasia (PED) after disappearance of puncta is problematical. In some instances, however, the phenotypic and radiographic characteristics may persist and permit a retrospective diagnosis of PED in persons with unclassified bone dysplasia or bone changes of unknown origin. We report a boy aged 8 years who presented with unusual bony abnormalities that were consistent with a diagnosis of PED.     

Bi‐allelic IARS mutations in a child with intra‐uterine growth retardation,neonatal cholestasis,and mild developmental delay

Recently, bi‐allelic mutations in cytosolic isoleucyl‐tRNA synthetase (IARS) have been described in three individuals with growth delay, hepatic dysfunction, and neurodevelopmental disabilities. Here we report an additional subject with this condition identified by whole‐exome sequencing. Our findings support the association between this disorder and neonatal cholestasis with distinct liver pathology. Furthermore, we provide functional data on two novel missense substitutions and expand the phenotype to include mild developmental delay, skin hyper‐elasticity, and hypervitaminosis D.     

Fabricating a Shell-Core Delayed Release Tablet Using Dual FDM 3D Printing for Patient-Centred Therapy

Purpose

Individualizing gastric-resistant tablets is associated with major challenges for clinical staff in hospitals and healthcare centres. This work aims to fabricate gastric-resistant 3D printed tablets using dual FDM 3D printing.

Methods

The gastric-resistant tablets were engineered by employing a range of shell-core designs using polyvinylpyrrolidone (PVP) and methacrylic acid co-polymer for core and shell structures respectively. Filaments for both core and shell were compounded using a twin-screw hot-melt extruder (HME). CAD software was utilized to design a capsule-shaped core with a complementary shell of increasing thicknesses (0.17, 0.35, 0.52, 0.70 or 0.87 mm). The physical form of the drug and its integrity following an FDM 3D printing were assessed using x-ray powder diffractometry (XRPD), thermal analysis and HPLC.

Results

A shell thickness ≥0.52 mm was deemed necessary in order to achieve sufficient core protection in the acid medium. The technology proved viable for incorporating different drug candidates; theophylline, budesonide and diclofenac sodium. XRPD indicated the presence of theophylline crystals whilst budesonide and diclofenac sodium remained amorphous in the PVP matrix of the filaments and 3D printed tablets. Fabricated tablets demonstrated gastric resistant properties and a pH responsive drug release pattern in both phosphate and bicarbonate buffers.

Conclusions

Despite its relatively limited resolution, FDM 3D printing proved to be a suitable platform for a single-process fabrication of delayed release tablets. This work reveals the potential of dual FDM 3D printing as a unique platform for personalising delayed release tablets to suit an individual patient’s needs.

     

Familial infantile bilateral striatal necrosis: clinical features and response to biotin treatment

BACKGROUND: Infantile bilateral striatal necrosis (IBSN) encompasses several syndromes of bilateral symmetric, spongy degeneration of the caudate nucleus, putamen, and globus pallidus. The familial form of IBSN is rare, and inheritance is either autosomal recessive or maternal. METHOD: The authors describe an Israeli Bedouin kindred in which 15 children born to consanguineous parents were affected with familial IBSN. They evaluated the clinical and radiologic evolution of the disease in 11 patients and the cerebral pathologic findings in one patient. Three of the children were treated with oral biotin 100 mg/day. RESULTS: Inheritance was apparently autosomal recessive. The untreated children had a similar clinical picture including developmental arrest beginning at the age of 7 to 15 months, choreoathetosis, and dysphagia. Pendular nystagmus appeared at a late stage. MRI, performed at various stages of the disease, showed severe basal ganglia atrophy. Postmortem study in one patient showed severe atrophy of the lenticular nuclei with gliosis and loss of neurons. Biotin, 100 mg/day, administered to the proband over a period of 15 months, may have slowed progression. In two other children treatment was initiated earlier and appeared to arrest or improve disease. CONCLUSIONS: Familial infantile bilateral striatal necrosis was inherited as an autosomal recessive trait. Clinical features included developmental arrest, dysphagia, and choreoathetosis. Imaging and pathology showed atrophy and degeneration of the basal ganglia. Oral biotin may have benefited three children.     

Survival of Prosthodontic Restorations Luted with Resin-Based versus Composite-Based Cements: Retrospective Cohort Study

The purpose of this study was to evaluate clinical performance, survival, and complications of indirect composite inlays, onlays, and overlays on posterior teeth. Digital records of 282 patients treated between 2014 and 2018 were accessed and analyzed retrospectively. The included patients received 469 composite restorations luted with seven different resin-based types of cement, i.e., Filtek Ultimate Flow, Enamel Plus, Relyx Ultimate, Harvard Premium Flow, Relyx Unicem, Filtek Bulk Fill Flowable, and Filtek Ultimate. The restorations had been clinically and radiographically evaluated annually. The mechanical and clinical complications, e.g., debonding, fracture, and secondary caries, were evaluated and recorded. The examined restorations exhibited a high survival rate (84.9%), and failure was found in only 71 cases. Fracture was the most common cause (n = 36), followed by prosthetic work release (n = 19) and secondary caries (n = 16). There was a statistically significant difference between failure and cement material (Sig. < 0.001); the composite-based cements (87.2%) had a high survival rate compared to the resin-based cement (72.7%). Similarly, the cements with high viscosity (90.2%) had significantly higher survival rates than the low-viscosity cements (78.9%). Moreover, onlays showed higher longevity compared to overlays (Sig. = 0.007), and patients aged under 55 years showed less complications (Sig. = 0.036). Indirect composite restoration was a successful solution to tooth structure loss. The material of the cementation is an important part of the success. Higher survival rate was found in our study when the fixation materials with high viscosity were used, thus suggesting using these materials with indirect restorations. Composite-based cements had significantly higher survival rate than resin-based cements.     

Direct Crosstalk Between Cancer and Osteoblast Lineage Cells Fuels Metastatic Growth in Bone via Auto‐Amplification of IL‐6 and RANKL Signaling Pathways

The bone microenvironment and its modification by cancer and host cell interactions is a key driver of skeletal metastatic growth. Interleukin‐6 (IL‐6) stimulates receptor activator of NF‐κB ligand (RANKL) expression in bone cells, and serum IL‐6 levels are associated with poor clinical outcomes in cancer patients. We investigated the effects of RANKL on cancer cells and the role of tumor‐derived IL‐6 within the bone microenvironment. Using human breast cancer cell lines to induce tumors in the bone of immune‐deficient mice, we first determined whether RANKL released by cells of the osteoblast lineage directly promotes IL‐6 expression by cancer cells in vitro and in vivo. We then disrupted of IL‐6 signaling in vivo either via knockdown of IL‐6 in tumor cells or through treatment with specific anti‐human or anti‐mouse IL‐6 receptor antibodies to investigate the tumor effect. Finally, we tested the effect of RANK knockdown in cancer cells on cancer growth. We demonstrate that osteoblast lineage‐derived RANKL upregulates secretion of IL‐6 by breast cancers in vivo and in vitro. IL‐6, in turn, induces expression of RANK by cancer cells, which sensitizes the tumor to RANKL and significantly enhances cancer IL‐6 release. Disruption in vivo of this auto‐amplifying crosstalk by knockdown of IL‐6 or RANK in cancer cells, or via treatment with anti‐IL‐6 receptor antibodies, significantly reduces tumor growth in bone but not in soft tissues. RANKL and IL‐6 mediate direct paracrine‐autocrine signaling between cells of the osteoblast lineage and cancer cells, significantly enhancing the growth of metastatic breast cancers within bone. © 2014 American Society for Bone and Mineral Research.     

Primary reservoirs of Streptococcus mutans and their relationship to caries experience in adults with good oral hygiene

Primary reservoirs of Streptococcus mutans were identified in a group of 21 adults with intact dentitions and good oral hygiene by obtaining multiple plaque samples from all available tooth surfaces. Routine cultural methods and a rapid plate scoring method employing a 7-point ordinal scale were used to assess S. mutans levels. Oral hygiene status (DI-S) and caries experience (DMFT and DMFS) were determined clinically. Primary S. mutans reservoirs (high scores) were restricted essentially to the posterior interproximal areas and occasionally in the occlusal pits and fissures of partially erupted mandibular third molars. An anterior to posterior gradient of increasing S. mutans scores was observed for interproximal sites. Oral hygiene scores correlated poorly with DMFT, DMFS and the S. mutans scores obtained for different anatomic locations.