Dhamija, Radhika

Glutathione synthetase (GSS) deficiency is an extremely rare autosomal recessive inborn error of metabolism. This metabolic disorder is caused by mutations in the GSS gene, which encodes GSS—an enzyme that catalyses the ATP-dependent conversion of γ-glutamyl-cysteine and glycine to glutathione. Low glutathione impairs the cellular antioxidant defence mechanism, leaving cells susceptible to oxidative stress and damage.

Background/Objectives: Pectus excavatum (PEx) is considered, at least partially, a familial disorder. A variety of inheritance patterns, associations with genetic syndromes, and pathogenic variants have been reported. However, the etiology of this condition is still not completely understood, and no known genes have been identified as definitive contributors. Methods: Family members with a confirmed PEx diagnosis (one proband and two first-degree relatives) and non-affected members were recruited into this study. Exome sequencing was performed on all affected familial PEx cases to systematically screen for candidate genes that are likely to be causative for PEx, and on non-affected family members for variant segregation analysis. Results: Ten families, with three affected members each, participated, providing thirty familial PEx cases. Different inheritance patterns were represented across the ten pedigrees, with possible incomplete penetrance. Genetic variants in REST (essential for neuronal development and associated with pectus deformities in prior studies), SMAD4 (variants can predispose individuals to thoracic aortic diseases), and COL5A (associated with Ehlers–Danlos syndrome and Fibromuscular dysplasia) were initially identified as potentially linked to the development of pectus deformities and segregated with the phenotype. No variants were shared across families in the studied population. Conclusions: Germline exome sequencing of families with multiple individuals affected by PEx in our study identified potential gene candidates linked to PEx. These candidates are private to individual families and no strong candidates shared across multiple families were identified. These findings suggest that the inheritance of PEx may not be strongly related to a shared single genetic variant in known genes. Given the accumulating evidence for the genetic basis of familial PEx, further studies, including polygenic analyses, as well as assessment of the non-coding genome and possible epigenetic markers are warranted.

Purpose: To describe a case of retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) to enhance early recognition of this often-missed diagnosis. Methods: A case report is presented. Results: A 50-year-old woman with a history of Raynaud phenomenon, memory difficulties, and a family history of strokes was referred for evaluation of a bilateral, small-vessel, occlusive disease refractory to immunosuppressive therapy. An extensive workup for treatable causes was unrevealing. Fifteen months after presentation, brain imaging showed white-matter lesions and dystrophic calcification, which led to the discovery of a pathogenic variant in TREX1 and the diagnosis of RVCL-S. Conclusions: Retina specialists play a critical role in the timely diagnosis of RVCL-S. Although the findings in this condition can mimic those in other common retinal vascular disorders, there are key characteristics that increase the suspicion for RVCL-S. Early recognition might decrease unnecessary therapies and procedures.

Introduction: Spontaneous coronary artery dissection (SCAD) is a term used to define a spontaneous separation of the coronary artery wall not related to underlying risk factors, such as trauma or underlying atherosclerotic disease. While SCAD has a range of different etiologies, with fibromuscular dysplasia being the most common, most cases of SCAD have no concomitant arteriopathy. Case Report: Here we describe a case of a patient who presented to our institution with SCAD and evidence of an asymptomatic arteriopathy involving extracranial segments of the carotid and vertebral arteries, later found to have a pathogenic variant in the FBN1 gene and ultimately diagnosed with Marfan syndrome. This has only been rarely described in the literature as an etiology for SCAD. Conclusion: Although rare, it is important to consider underlying connective tissue disorders in patients presenting with spontaneous coronary artery dissection and arteriopathy without underlying cardiovascular risk factors.

AbstractNeurofibromatosis type 1 (NF1) is a common neurocutaneous disorder characterized by development of pigmentary skin changes, neurogenic tumors, and other manifestations involving multiple organ systems. Penetrance is complete, though expressivity is quite variable even among the family members. Given that NF1 is a common hereditary condition, existence of a second genetic disorder in NF1 patients is not unexpected. During comprehensive evaluations of individuals with NF1, we encountered 11 patients with dual diagnosis who contributed to phenotypic complexity and challenges for long‐term management. Examples include Prader–Willi Syndrome, Autosomal Dominant Polycystic Kidney Disease, Down syndrome, infantile myofibromatosis, Craniosynostosis, cleft lip and palate, 47,XYY, 22q11.2 duplication, 15q13.3 deletion syndrome, and BRCA2‐ and ATM‐ related cancer predisposition syndromes. Presence of dysmorphism, developmental delay, atypical tumors, and family history of other genetic disorders including cancers appears as determinants to consider a second genetic etiology and helps to differentiate from an extreme phenotypic spectrum of NF1. Clinicians should have high index of suspicion to exclude coexisting disorders, as apart from providing comprehensive medical care. This also has potential implications in genetic counseling. Long‐term effects of the synergistic mechanisms leading to phenotypic complexity and patient outcomes are yet to be characterized, with follow‐up needed.

AbstractNoonan syndrome (NS) is an autosomal dominant condition with variable expressivity most commonly due to a germline pathogenic variant in PTPN11, which encodes the protein tyrosine phosphatase SHP‐2. Gain‐of‐function variants in PTPN11 are known to promote oncogenic behavior in affected tissues. We report the clinical description of a young adult male presenting with relapsing ganglioneuromas, dysmorphic features, cardiac abnormalities, and multiple lentigines, strongly suspicious for NS. Solid tumor testing identified the recurrent pathogenic c.922G>A (p.Asn308Asp) in PTPN11. Proband and parental blood sampling testing confirmed c.922G>A as a de novo germline alteration. Comprehensive literature review of solid tumors specifically associated to PTPN11, indicates that this is the first documentation of ganglioneuroma and its clinical recurrence after resection in conjunction with a genetically confirmed NS diagnosis. The findings in our patient further extend the list of neuroblastic and neural crest‐derived neoplasms associated with this condition.