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Here, we report an individual, eventually diagnosed with HMG-CoA synthase deficiency, who presented with a cyclic vomiting phenotype. HMG-CoA synthase deficiency is a rare disorder affecting ketone body synthesis in which affected individuals typically present at a young age with hypoketotic hypoglycemia, lethargy, encephalopathy, and hepatomegaly, usually triggered by catabolism (e.g., infection or prolonged fasting). This individual presented with recurrent episodes of vomiting and lethargy, often associated with hypoglycemia or hyperglycemia, at 3 years of age. Metabolic labs revealed nonspecific abnormalities in her urine organic acids (showing mild elevation of dicarboxylic acids with relatively low excretion of ketones) and a normal acylcarnitine profile. Given her clinical presentation, as well as a normal upper gastrointestinal series, esophagogastroduodenoscopy with biopsies, and abdominal ultrasound, she was diagnosed with cyclic vomiting syndrome at 3 years of age. Molecular testing completed at 7 years of age revealed a previously reported pathogenic sequence variant (c.1016+1G>A) and a novel likely pathogenic deletion (1.57 kB deletion, including exon 1) within HMGCS2 consistent with HMG-CoA synthase deficiency. This individual’s presentation, mimicking cyclic vomiting syndrome, widens the clinical spectrum of HMG-CoA synthase deficiency. In addition, this case highlights the importance of molecular genetic testing in such presentations, as this rare disorder lacks specific metabolic markers.

Here, we report an individual, eventually diagnosed with HMG-CoA synthase deficiency, who presented with a cyclic vomiting phenotype. HMG-CoA synthase deficiency is a rare disorder affecting ketone body synthesis in which affected individuals typically present at a young age with hypoketotic hypoglycemia, lethargy, encephalopathy, and hepatomegaly, usually triggered by catabolism (e.g., infection or prolonged fasting). This individual presented with recurrent episodes of vomiting and lethargy, often associated with hypoglycemia or hyperglycemia, at 3 years of age. Metabolic labs revealed nonspecific abnormalities in her urine organic acids (showing mild elevation of dicarboxylic acids with relatively low excretion of ketones) and a normal acylcarnitine profile. Given her clinical presentation, as well as a normal upper gastrointestinal series, esophagogastroduodenoscopy with biopsies, and abdominal ultrasound, she was diagnosed with cyclic vomiting syndrome at 3 years of age. Molecular testing completed at 7 years of age revealed a previously reported pathogenic sequence variant (c.1016+1G>A) and a novel likely pathogenic deletion (1.57 kB deletion, including exon 1) within HMGCS2 consistent with HMG-CoA synthase deficiency. This individual's presentation, mimicking cyclic vomiting syndrome, widens the clinical spectrum of HMG-CoA synthase deficiency. In addition, this case highlights the importance of molecular genetic testing in such presentations, as this rare disorder lacks specific metabolic markers. [ABSTRACT FROM AUTHOR]

The phenotype of individuals with glycogen storage disease (GSD) IX appears to be highly variable, even within subtypes. Features include short stature, fasting hypoglycemia with ketosis, hepatomegaly, and transaminitis. GSD IXɑ2 is caused by hemizygous pathogenic variants in PHKA2, and results in deficiency of the phosphorylase kinase enzyme, particularly in the liver. Like other GSDs, GSD IXɑ2 can present with hypoglycemia and post-prandial lactic acidosis, but has never been reported in a newborn, nor with lactic acidosis as the presenting feature. Here we describe the clinical presentation and course of a newborn boy with profound neonatal lactic and metabolic acidosis, renal tubulopathy, and sensorineural hearing loss (SNHL) diagnosed with GSD IXɑ2 through exome sequencing. Review of the literature suggests this case represents an atypical and severe presentation of GSD IXɑ2 and proposes expansion of the phenotype to include neonatal lactic acidosis and renal tubulopathy.

The synthesis of yttria‐stabilized zirconia nanoparticles with a fine control on the chemical composition and the distribution of yttrium cations is of major interest to master the mechanical, optical or ionic conduction properties of the final material. However, a fine control of this chemical homogeneity within the particles, especially above 5 mol.% of yttria (Y2O3), is challenging with conventional synthesis routes. In the present study, for the first time the interest of using supercritical sol–gel like synthesis is demonstrated for the continuous production in a single step of high quality zirconia (ZrO2) nanocrystals of 7 nm stabilized with Y2O3 without post‐treatment. Three compositions are investigated, i.e., 1.5, 3, and 8 mol.% of Y2O3 and in‐depth physico‐ chemical characterizations such as X‐ray diffraction, total X‐ray scattering, High‐resolution electron microscopy, Raman and X‐ray photoelectron spectroscopy are performed to asses and thus prove the successful synthesis of these different compositions while keeping a good chemical homogeneity. This enables to confirm that this original process leads to a unique and fine structural control for such small yttria‐doped zirconia nanocrystals. [ABSTRACT FROM AUTHOR]

Although decreased citrulline is used as a newborn screening (NBS) marker to identify proximal urea cycle disorders (UCDs), it is also a feature of some mitochondrial diseases, including MT‐ATP6 mitochondrial disease. Here we describe biochemical and clinical features of 11 children born to eight mothers from seven separate families who were identified with low citrulline by NBS (range 3–5 μM; screening cutoff >5) and ultimately diagnosed with MT‐ATP6 mitochondrial disease. Follow‐up testing revealed a pattern of hypocitrullinemia together with elevated propionyl‐(C3) and 3‐hydroxyisovaleryl‐(C5‐OH) acylcarnitines, and a homoplasmic pathogenic variant in MT‐ATP6 in all cases. Single and multivariate analysis of NBS data from the 11 cases using Collaborative Laboratory Integrated Reports (CLIR; https://clir.mayo.edu) demonstrated citrulline <1st percentile, C3 > 50th percentile, and C5‐OH >90th percentile when compared with reference data, as well as unequivocal separation from proximal UCD cases and false‐positive low citrulline cases using dual scatter plots. Five of the eight mothers were symptomatic at the time of their child(ren)'s diagnosis, and all mothers and maternal grandmothers evaluated molecularly and biochemically had a homoplasmic pathogenic variant in MT‐ATP6, low citrulline, elevated C3, and/or elevated C5‐OH. All molecularly confirmed individuals (n = 17) with either no symptoms (n = 12), migraines (n = 1), or a neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP) phenotype (n = 3) were found to have an A or U mitochondrial haplogroup, while one child with infantile‐lethal Leigh syndrome had a B haplogroup. [ABSTRACT FROM AUTHOR]