Mild-to-moderate bleeding disorders are underdiagnosed, with many individuals classified as having no clear cause for their bleeding. Accurate diagnosis remains challenging and requires comprehensive clinical assessment, detailed laboratory testing, and advanced genetic testing. This study aimed to elucidate the relevance of an integrated approach for diagnosing patients with mild-to-moderate bleeding disorders by reevaluating 2 cases previously labeled with an undefined cause. Two young siblings with unexplained bleeding tendencies were referred for evaluation. Bleeding score were assessed using the International Society on Thrombosis and Haemostasis bleeding assessment tool questionnaire. Platelet phenotyping included blood count, blood film, coagulation tests, light transmission aggregometry, flow cytometry, western blotting, and transmission electron microscopy. Genetic analysis involved whole-exome sequencing (WES) and pathogenicity assessment of candidate variants. Both siblings exhibited mild-to-moderate bleeding (bleeding score, 11 and 3, respectively). Blood count, coagulation factor tests, and light transmission aggregometry response to several agonists were normal. Blood film showed large and hypogranular platelets. Flow cytometry revealed reduced α-granule secretion upon ADP and TRAP6 stimulation. WES identified a homozygous variant in VPS33B (c.1225+5G>C) predicted to disrupt splicing. Immunoblotting confirmed null VPS33B expression and reduced von Willebrand factor levels. Transmission electron microscopy showed abnormal vacuole content and significantly reduced α-granules, while δ-granules and mitochondria remained intact. This study reports a novel homozygous variant in VPS33B, leading to platelet dysfunction and bleeding diathesis based on α-granule defect and syndromic manifestations. Our findings highlight the importance of an integrated diagnostic approach, including WES, and expand the clinical and genetic spectrum of arthrogryposis, renal dysfunction, and cholestasis syndrome.

The patients with Arthrogryposis-Renal dysfunction-Cholestasis (ARC) syndrome have genetic susceptibility to the opportunistic infections due to the involvement of VPS33B (vacuolar protein sorting 33 homolog B) in phagolysosome fusion in macrophages. Detailed pathologic studies in ARC patients are missing in literature due to the lack of autopsy. We described the first autopsy case of ARC syndrome in a 2-month-old male infant. His death was due to recurrent sepsis and multiorgan failure despite the appropriate poly-antibiotic therapy and supportive care. The autopsy showed invasive renal candidiasis including bilateral destructive pyelonephritis, pelvic obstructive fungal bezoars, and right large perinephric abscess. The main other findings included severe chronic liver changes and pneumonia. Liver exhibited intrahepatocyte cholestasis, large multinucleated hepatocytes, diffuse portal, bridging and perivenular fibrosis, and interlobular bile duct proliferation. The neuropathologic examination was unremarkable. This case report highlights 3 novel findings. The ARC syndrome-related immunodeficiency may predispose to renal fungal bezoars and perinephric abscess. Cholestatic stress may result in the proliferation of interlobular ducts as an adaptive response. Absence of spinal motor neuron degeneration suggests that the neurogenic amyotrophy is due to the lack of synaptic vesicle trafficking and membrane fusion rather than the defect in cell survival-related autophagosome-lysosome fusion.

Arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome, a rare autosomal recessive disorder, exhibits genetic heterogeneity with the VIPAS39 gene pathological variants being a distinct contributor. We present two related patients from Kosovo, describing the clinical, genetic, and therapeutic aspects of the syndrome. The identified novel VIPAS39 pathological variants (c.762G > A; c.1064_1082delinsAGTG) emphasize the complex phenotypic expression of ARC syndrome. A systematic literature review identified 8 VIPAS39-related ARC cases with notable variability in clinical features. Prognostically, patients fell into severe and milder groups, with some reaching adolescence. Our report aligns with others noting milder ARC courses and emphasizes the value of genetic testing, especially in atypical presentations. Challenges included incomplete literature data, early mortality affecting diagnostic workup, and limited VIPAS39-related ARC cases. Comparisons with the more prevalent VPS33B pathological variants revealed no distinct clinical differences. Our study expands understanding of ARC syndrome, highlighting its genetic diversity and clinical variability. Milder presentations underscore diagnostic challenges and the potential prevalence of undiagnosed cases. Increased awareness and comprehensive genetic testing are crucial for early and accurate diagnosis.

Advances in molecular genetics have uncovered causative genes responsible for neonatal cholestasis. Panel-based next-generation sequencing has been used clinically in infants with neonatal cholestasis. We aimed to evaluate the clinical application of single-gene testing and next-generation sequencing and to develop a diagnostic algorithm for neonatal intrahepatic cholestasis. From January 2010 to July 2021, patients suspected of having neonatal intrahepatic cholestasis were tested at the Seoul National University Hospital. If there was a clinically suspected disease, single-gene testing was performed. Alternatively, if it was clinically difficult to differentiate, a neonatal cholestasis gene panel test containing 34 genes was performed. Of the total 148 patients examined, 49 (33.1%) were received a confirmed genetic diagnosis, including 14 with Alagille syndrome, 14 with neonatal intrahepatic cholestasis caused by citrin deficiency, 7 with Dubin-Johnson syndrome, 5 with arthrogryposis-renal dysfunction-cholestasis syndrome, 5 with progressive familial intrahepatic cholestasis type II, 1 with Rotor syndrome, 1 with Niemann-Pick disease type C, 1 with Kabuki syndrome, and 1 with Phenylalanyl-tRNA synthetase subunit alpha mutation. Sixteen novel pathogenic or likely pathogenic variants of neonatal cholestasis were observed in this study. Based on the clinical characteristics and laboratory findings, we developed a diagnostic algorithm for neonatal intrahepatic cholestasis by integrating single-gene testing and next-generation sequencing. Alagille syndrome and neonatal intrahepatic cholestasis caused by citrin deficiency were the most common diseases associated with genetic neonatal cholestasis. Single-gene testing and next-generation sequencing are important and complementary tools for the diagnosis of genetic neonatal cholestasis.

This current case series adds to the spectrum of Arthrogryposis renal dysfunction cholestasis (ARC)-associated variants. Increased awareness and early genetic testing for ARC are suggested in cases with failure to thrive, renal tubular dysfunction, and rickets, even when the degree of cholestasis is mild. Prompt identification and intervention may improve the quality of life.