Structural analysis of new compound heterozygous variants in PEPD gene identified in a patient with Prolidase Deficiency diagnosed by exome sequencing

Further Clinical Delineation of Prolidase Deficiency Associated with c.1103T>G Variant

Introduction

Prolidase deficiency is a rare multisystemic disease associated with collagen metabolism. Clinical manifestations and age of onset are highly variable. Prolidase deficiency is caused by homozygous variants in the PEPD gene. In this report, three siblings with c.1103T>G (L368R) variant in the PEPD gene are presented. They had features not described in the literature and marked intrafamilial clinical heterogeneity. This is the first family of Syrian ancestral origin with prolidase deficiency.

Case Presentation

We performed whole-exome sequencing for the index case, and detected a homozygous c.1103T>G variant, in the PEPD gene. All family members were then screened for the same variant by Sanger sequencing analysis. Two siblings were found to be homozygous, and one of them had not yet developed clinical symptoms.

Conclusion

Our data expand the clinical spectrum of prolidase deficiency. It also improves our knowledge of phenotype and genotype relationships of prolidase deficiency patients.

Multiorgan Failure and Sepsis in an ICU Patient with Prolidase Enzyme Deficiency-The Specificity of Treatment and Care: A Case Report

Background and Objectives: Prolidase deficiency (PD) is a rare, life-threatening, genetically determined disease with an incidence of 1-2 cases per 1 million births. The disease inhibits collagen synthesis, which leads to organ and systems failure, including hepato- and splenomegaly, immune disorders, chronic ulcerative wounds, respiratory infections, and pulmonary fibrosis. The complexity of the problems associated with this disease necessitates a comprehensive approach and the involvement of an interdisciplinary team. The objective was to present the treatment and care plan, as well as complications of PD, in a young woman following admission to an intensive care unit (ICU). Materials and Methods: A retrospective observational single-case study. Results: A 26-year-old woman with PD was hospitalized in the ICU for acute respiratory failure. The presence of difficult-to-heal extensive leg ulcers and the patient's immunocompromised condition resulted in the development of sepsis with multiple organ failure (respiratory and circulatory, liver and kidney failure). Complex specialized treatment consisting of wound preparation, limb amputation, the minimization of neuropathic pain, mechanical ventilation, renal replacement therapy, circulatory stabilization, and the prevention of complications of the disease and of therapy were applied. On the 83rd day of hospitalization, the patient expired. Conclusions: Despite the use of complex treatment and care, due to the advanced nature of the disease and the lack of therapies with proven efficacy, treatment was unsuccessful. There is a need for evidence-based research to develop effective treatment guidelines for PD.

A novel PRRX1 loss-of-function variation contributing to familial atrial fibrillation and congenital patent ductus arteriosus

Atrial fibrillation (AF) represents the most common type of sustained cardiac arrhythmia in humans and confers a significantly increased risk for thromboembolic stroke, congestive heart failure and premature death. Aggregating evidence emphasizes the predominant genetic defects underpinning AF and an increasing number of deleterious variations in more than 50 genes have been involved in the pathogenesis of AF. Nevertheless, the genetic basis underlying AF remains incompletely understood. In the current research, by whole-exome sequencing and Sanger sequencing analysis in a family with autosomal-dominant AF and congenital patent ductus arteriosus (PDA), a novel heterozygous variation in the PRRX1 gene encoding a homeobox transcription factor critical for cardiovascular development, NM_022716.4:c.373G>T;p.(Glu125^*), was identified to be in co-segregation with AF and PDA in the whole family. The truncating variation was not detected in 306 unrelated healthy individuals employed as controls. Quantitative biological measurements with a reporter gene analysis system revealed that the Glu125^*-mutant PRRX1 protein failed to transactivate its downstream target genes SHOX2 and ISL1, two genes that have been causally linked to AF. Conclusively, the present study firstly links PRRX1 loss-of-function variation to AF and PDA, suggesting that AF and PDA share a common abnormal developmental basis in a proportion of cases.