EVIDENCE, an automated variant prioritization system, has been developed to facilitate whole exome sequencing analyses. This study investigated the diagnostic yield of EVIDENCE in patients with suspected genetic disorders. DNA from 330 probands (age range, 0-68 years) with suspected genetic disorders were subjected to whole exome sequencing. Candidate variants were identified by EVIDENCE and confirmed by testing family members and/or clinical reassessments. EVIDENCE reported a total 228 variants in 200 (60.6%) of the 330 probands. The average number of organs involved per patient was 4.5 ± 5.0. After clinical reassessment and/or family member testing, 167 variants were identified in 141 probands (42.7%), including 105 novel variants. These variants were confirmed as being responsible for 121 genetic disorders. A total of 103 (61.7%) of the 167 variants in 95 patients were classified as pathogenic or probably to be pathogenic before, and 161 (96.4%) variants in 137 patients (41.5%) after, clinical assessment and/or family member testing. Factor associated with a variant being regarded as causative includes similar symptom Go Hun Seo, Taeho Kim, and In Hee Choi contributed equally to this work.

BackgroundAmbroxol (ABX) has been suggested as an augmentative pharmacological agent for neuronopathic Gaucher disease (nGD). This study assessed the long-term safety and efficacy of combined therapy with high-dose ABX and enzyme replacement therapy (ERT) in nGD.MethodsABX+ERT therapy was administered for 4.5 years in four patients with nGD. ABX was initiated at a dose of 1.5 mg/kg/day, and the dose was escalated up to 27 mg/kg/day. The target plasma level was 10 µmol/L or less. The changes in glucocerebrosidase activity, biochemical, safety and neurocognitive findings were assessed.ResultsEnhanced residual GCcase activity was observed in all patients, as evidenced in both in vitro and in vivo studies. During the first 2 years of study with ABX (up to 21 mg/kg/day), mean seizure frequencies and neurocognitive function worsened. After ABX dosage was increased up to 27 mg/kg/day of ABX, its trough plasma concentration was 3.2–8.8 µmol/L. Drug-to-drug interaction, especially with antiepileptic drug significantly affected the pharmacokinetic parameters of ABX. Importantly, at 27 mg/kg/day of ABX, the seizure frequencies markedly decreased from the baseline, and the neurocognitive function was improved. In addition, Lyso-Gb1, a biomarker for the severity and progression of GD, was normalised in all patients. High-dose ABX was well-tolerated with no severe adverse events.ConclusionsLong-term treatment with high-dose ABX+ERT was safe and might help to arrest the progression of the neurological manifestations in GD.

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Background The diagnostic yield of whole-exome sequencing (WES) varies from 30%–50% among patients with mild to severe neurodevelopmental delay (NDD)/intellectual disability (ID). Routine retrospective reanalysis of undiagnosed patients has increased the total diagnostic yield by 10–15%. Here, we performed proband-only WES of 1065 patients with NDD/ID and applied a prospective, daily reanalysis automated pipeline to patients without clinically significant variants to facilitate diagnoses. Methods The study included 1065 consecutive patients from 1056 nonconsanguineous unrelated families from 10 multimedical centers in South Korea between April 2018 and August 2021. WES data were analyzed daily using automatically updated databases with variant classification and symptom similarity scoring systems. Results At the initial analysis, 402 patients from 1056 unrelated families (38.0%, 402/1,056 families) had a positive genetic diagnosis. Daily prospective, automated reanalysis resulted in the identification of 34 additional diagnostic variants in 31 patients (3%), which increased our molecular diagnostic yield to 41% (433/1056 families). Among these 31 patients, 26 were diagnosed with 23 different diseases that were newly discovered after 2019. The time interval between the first analysis and the molecular diagnosis by reanalysis was 1.2 ± 0.9 years, which was shorter in the patients enrolled during the latter part of the study period. Conclusion Daily updated databases and reanalysis systems enhance the diagnostic performance in patients with NDD/ID, contributing to the rapid diagnosis of undiagnosed patients by applying the latest molecular genetic information.

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Oral supplementation of vitamin D can be inefficient in patients with vitamin D deficiency caused by intestinal malabsorption. This study investigated the efficacy and safety of parenteral vitamin D supplementation in infants and children with vitamin D deficiency caused by intestinal malabsorption. Methods: This study included 11 patients with vitamin D deficiency who were unresponsive to oral vitamin D or were unable to try oral vitamin D therapy due to underlying conditions. All patients were treated with weekly intramuscular injection of cholecalciferol 50,000 IU. Radiological findings and biochemical parameters including serum calcium, phosphorus, alkaline phosphatase, 25-hydroxyvitamin D3 (25(OH)D3), and parathyroid hormone levels were reviewed retrospectively. Results: Underlying diseases included small bowel atresia (n=3), necrotizing enterocolitis (n=3), congenital megacolon (n=2), chronic intestinal pseudoobstruction (n=1), congenital mesenteric band (n=1), and Crohn disease (n=1). Three patients exhibited rickets on X-ray findings. The mean duration of treatment was 4.8±2.9 weeks. The alkaline phosphatase levels were decreased from 710±650 IU/L to 442±284 IU/L (P=0.143). The 25(OH)D3 level was increased from 6.0±3.4 ng/ mL to 50.4±28.8 ng/mL (P=0.008) after 3 months. Two patients with rickets showed improved radiologic findings after parenteral treatment. Conclusion: Parenteral vitamin D therapy was effective and safe in patients with vitamin D deficiency caused by intestinal malabsorption. Long-term follow-up is needed to establish the efficacy of parenteral vitamin D therapy in a large number of patients.

2 AbstractsPurpose: We developed an automated interpretation system for the whole process of Whole exome sequencing (WES) including raw data processing, variant calling, variant interpretation, and measurement of phenotypic similarity between the patient and each disease. This study was to investigate diagnostic yield and clinical utility of our new system that assists clinicians with diagnosis of patients with suspected genetic disorders. Methods: WES was performed a total of 194 patients (age range 0-68 years) with suspected genetic disorder. The patient inclusion criteria were delayed development within age of 5 months, multiple congenital anomalies with dysmorphic features, strongly suggestive features of monogenic disorder or genetically heterogeneous disorder, or not diagnosed despite performing genetic investigation. Results: WES reported 180 variants, of which 110 variants were confirmed by segregation analysis and 94 patients (48.4%) were diagnosed with 89 genetic disorders. There was no difference of diagnostic rate (48.9 %, 71/145 vs. 46.9%, 23/49, P > 0.05) and duration of the diagnostic odyssey (2.8 ± 3.3 vs. 4.1 ± 5.1, P= 0.293) between group with and without genetic test before WES. There was no significant difference in the distribution of clinical symptoms between the patients who were diagnosed with and without genetic disorder. Forty four percent of total patients filled only 9% of total symptom principal component analysis (PCA) space, and the remaining 56% of patients filled the other 91% of symptom PCA space. The two groups had similar genetic variant diversities (P = 0.899). ConclusionThis study showed improved diagnostic yield (48.4%) in patients with clinical heterogeneity by using automating variant interpretation. Diverse genetic variations were also observed in patients with similar symptoms. This study highlights the utility of automated 3 interpretation system of WES to clarify differential diagnosis in patients with suspected genetic disorder.

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