Angioid streaks in Pseudoxanthoma Elasticum: role of the p.R1268Q mutation in the ABCC6 gene

Cutis Laxa and the Value of Rhytidectomy: 4 Patients and Years of Follow-Up

The modalities of the esthetic treatment of cutis laxa (CL) patients have rarely been discussed. Here, the authors present 4 CL rhytidectomy cases. The surgery method was designed based on the traditional full-incision face-lift technique combined with lamellar superficial musculoaponeurotic system flap elevation and plication. Temporal, buccal, mandibular, and cervical regions were targeted. The shortest follow-up was 30 months, and the longest was 72. The results were assessed by subjective satisfaction and third-party photo evaluation. The subjective satisfaction was graded into worse than preoperation, no improvement, slight improvement, moderate improvement, and obvious improvement. The satisfaction rate was the sum of moderate and obvious improvement. Eighteen uncorrelated professionals participated in the third-party photo evaluation, in which the preoperative and follow-up photos were presented, and frontal, temporal, mid-face (including jowl), and cervical (including mandibular line) regions were evaluated as improved or nonimproved. The outcome of the subjective satisfaction was graded as no improvement (2/12, 16.7%), slight improvement (3/12, 25%), moderate improvement (4/12, 33.3%), and obvious improvement (3/12, 25%). The satisfaction rate was 58.3%, most investigators denied the frontal and temporal region improvement, 60% observed mid-face improvement, and 80% noticed cervical improvement. Most patients and their parents had positive attitudes towards the treatment results; however, the full expectation was not achieved. The cervical region maintained the best improvement after our treatment and the mid-face ranked second. This surgery method conduces to the esthetic requirement of CL patients; however, skin laxity remains a challenge.

Angioid Streaks in Pseudoxanthoma Elasticum

Pseudoxanthoma elasticum, or Gronblad-Strandberg syndrome, is an inherited disorder that involves multiple organ systems. The characteristic degeneration and calcification of the elastic fibers caused by this disease were first observed by Ferdinand Jean Darrier in 1896. We report a case of a 27-year-old female who was diagnosed with pseudoxanthoma elasticum based on a skin biopsy prior to her presentation to our ophthalmology outpatient clinic. The past ocular history of the patient was unremarkable for any previous eye complaint or surgery. Her ocular and fundus examination showed pigmented grayish irregular post choroidal crack-like linear dehiscence, forming a network-like pattern, originating at the optic disc and extending radially involving the macular area and the posterior pole in both eyes, representing bilateral angioid streaks. There were no clinical or optical coherent tomographic signs of choroidal neovascularization. Periodic follow up for patients with pseudoxanthoma elasticum is recommended to detect choroidal neovascularization which is a sight-threatening complication. Ophthalmologists should be aware of this association as early recognition and treatment are vital to prevent irreversible visual loss.

Rare Co-occurrence of Beta-Thalassemia and Pseudoxanthoma elasticum: Novel Biomolecular Findings

A number of beta-thalassemia patients, independently from the type of beta-thalassemia (β⁰ or β⁺) and blood transfusion requirements, may develop, after puberty, dermal, cardiovascular, and ocular complications associated with an ectopic mineralization phenotype similar to that observed in another rare genetic disorder, namely, Pseudoxanthoma elasticum (PXE). To date, the causes of these alterations in beta-thalassemia patients are not known, but it has been suggested that they could be the consequence of oxidative stress-driven epigenetic regulatory mechanisms producing an ABCC6 down-regulation. Since, in the last years, several genes have been associated to the ectopic mineralization phenotype, this study, for the first time, applied, on beta-thalassemia patients with ectopic mineralization phenotype, a multigene testing strategy. Selection of genes to be analyzed was done on the basis of (i) their genetic involvement in calcification diseases or (ii) their role in calcium-phosphate equilibrium. Although, due to the rarity of these conditions, a limited number of patients was analyzed, the detection of pathogenic variants represents the proof of concept that PXE and beta-thalassemia traits co-occur on a genetic basis and that, in addition to causative mutations, functional polymorphisms may further influence connective tissue manifestations. The use of a multigene-based next-generation sequencing represents a useful time- and cost-effective approach, allowing to identify sequence variants that might improve prognostic assessment and better management of these patients, especially in the current era of precision medicine aiming to identify individual optimal care based on a unique personal profile.

Pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is a genetic metabolic disease with autosomal recessive inheritance caused by mutations in the ABCC6 gene. The lack of functional ABCC6 protein leads to ectopic mineralization that is most apparent in the elastic tissues of the skin, eyes and blood vessels. The clinical prevalence of PXE has been estimated at between 1 per 100,000 and 1 per 25,000, with slight female predominance. The first clinical sign of PXE is almost always small yellow papules on the nape and sides of the neck and in flexural areas. The papules coalesce, and the skin becomes loose and wrinkled. The mid-dermal elastic fibers are short, fragmented, clumped and calcified. Dystrophic calcification of Bruch's membrane, revealed by angioid streaks, may trigger choroidal neovascularization and, ultimately, loss of central vision and blindness in late-stage disease. Lesions in small and medium-sized artery walls may result in intermittent claudication and peripheral artery disease. Cardiac complications (myocardial infarction, angina pectoris) are thought to be relatively rare but merit thorough investigation. Ischemic strokes have been reported. PXE is a metabolic disease in which circulating levels of an anti-mineralization factor are low. There is good evidence to suggest that the factor is inorganic pyrophosphate (PPi), and that the circulating low levels of PPi and decreased PPi/Pi ratio result from the lack of ATP release by hepatocytes harboring the mutant ABCC6 protein. However, the substrate(s) bound, transported or modulated by the ABCC6 protein remain unknown. More than 300 sequence variants of the ABCC6 gene have been identified. There is no cure for PXE; the main symptomatic treatments are vascular endothelial growth factor inhibitor therapy (for ophthalmic manifestations), lifestyle, lipid-lowering and dietary measures (for reducing vascular risk factors), and vascular surgery (for severe cardiovascular manifestations). Future treatment options may include gene therapy/editing and pharmacologic chaperone therapy.

Pseudoxanthoma elasticum: progress in diagnostics and research towards treatment : Summary of the 2010 PXE International Research Meeting

Pseudoxanthoma elasticum (PXE), a prototypic heritable disorder with ectopic mineralization, manifests with characteristic skin findings, ocular involvement, and cardiovascular problems. The classic forms of PXE are due to loss-of-function mutations in the ABCC6 gene, which encodes ABCC6, a putative transmembrane efflux transporter expressed primarily in the liver. While considerable progress has recently been made in understanding the molecular genetics and pathomechanisms of PXE, no effective or specific treatment is currently available for this disorder. PXE International, the premiere patient advocacy organization, organized a workshop in November 2010 to assess the current state of diagnostics and research to develop an agenda towards treatment of PXE. This overview summarizes the progress in PXE research, with emphasis on molecular therapies for this, currently intractable, disorder.