Biogenesis of the mitochondrial oxidative phosphorylation system, which produces the bulk of ATP for almost all eukaryotic cells, depends on the translation of 13 mtDNA-encoded polypeptides by mitochondria-specific ribosomes in the mitochondrial matrix. These mitoribosomes are dual-origin ribonucleoprotein complexes, which contain mtDNA-encoded rRNAs and tRNAs and $80 nucleus-encoded proteins. An increasing number of gene mutations that impair mitoribosomal function and result in multiple OXPHOS deficiencies are being linked to human mitochondrial diseases. Using exome sequencing in two unrelated subjects presenting with sensorineural hearing impairment, mild developmental delay, hypoglycemia, and a combined OXPHOS deficiency, we identified mutations in the gene encoding the mitochondrial ribosomal protein S2, which has not previously been implicated in disease. Characterization of subjects' fibroblasts revealed a decrease in the steady-state amounts of mutant MRPS2, and this decrease was shown by complexome profiling to prevent the assembly of the small mitoribosomal subunit. In turn, mitochondrial translation was inhibited, resulting in a combined OXPHOS deficiency detectable in subjects' muscle and liver biopsies as well as in cultured skin fibroblasts. Reintroduction of wild-type MRPS2 restored mitochondrial translation and OXPHOS assembly. The combination of lactic acidemia, hypoglycemia, and sensorineural hearing loss, especially in the presence of a combined OXPHOS deficiency, should raise suspicion for a ribosomal-subunit-related mitochondrial defect, and clinical recognition could allow for a targeted diagnostic approach. The identification of MRPS2 as an additional gene related to mitochondrial disease further expands the genetic and phenotypic spectra of OXPHOS deficiencies caused by impaired mitochondrial translation. Mitochondria are essential organelles that harbor the oxidative phosphorylation system (OXPHOS), an ATP-producing system encompassing five multi-subunit enzymatic complexes whose biogenesis is strictly dependent on the coordinated expression of genes encoded by nuclear and mitochondrial DNA (mtDNA). mtDNA encodes 13 subunits that are essential structural components of OXPHOS complexes I, III, IV, and V, in addition to encoding two rRNAs (16S and 12S) and 22 tRNAs required for the translation of the subunits. 1 Mitochondrial translation is executed by a dedicated translation machinery that includes many regulatory factors and a mitochondrial-specific ribosome composed of two subunits: the 28S (mt-SSU) and 39S (mt-LSU) ribosomal subunits. These subunits are large ribonucleoprotein complexes containing around 80 nuclear-encoded structural mitoribosomal proteins (MRPs) and mt-DNA-encoded RNAs: 12S rRNA in the mt-SSU and 16S rRNA, in addition to either mt-tRNA Val or mt-tRNA Phe , in the mt-LSU subunit. 2-5 The threedimensional structures of the mammalian 3,6,7 and human 2 mitoribosomes have only been elucidated recently. Considering the many factors involved in this process, it is not surpri...

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Cutis laxa (CL) is a connective tissue disorder, characterized by loose, inelastic, sagging skin. Both acquired and inherited (dominant, recessive, and X-linked) forms exist. Here, we describe a new phenotype, which overlaps with other known CL syndromes. Our patient has a unique combination of features in association with sagging, inelastic, wrinkled skin, including cataract, severe cardiomyopathy, abnormal fat distribution, improvement of skin-wrinkling with age, and white matter abnormalities but no significant histologic collagen or elastin abnormalities. Mutation analysis of known CL genes was negative. We suggest that our patient has a novel syndrome, with the main features of CL, intellectual disability, abnormal fat distribution, cardiomyopathy, and cataract.

Congenital disorders of N-glycosylation (CDG) form a rapidly growing group of more than 20 inborn errors of metabolism. Most patients are identified at the pediatric age with multisystem disease. There is no systematic review on the long-term outcome and clinical presentation in adult patients. Here, we review the adult phenotype in 78 CDG patients diagnosed with 18 different forms of N-glycosylation defects. Characteristics include intellectual disability, speech disorder and abnormal gait. After puberty, symptoms might remain non-progressive and patients may lead a socially functional life. Thrombosis and progressive symptoms, such as peripheral neuropathy, scoliosis and visual demise are specifically common in PMM2-CDG. Especially in adult patients, diagnostic glycosylation screening can be mildly abnormal or near-normal, hampering diagnosis. Features of adult CDG patients significantly differ from the pediatric phenotype. Non-syndromal intellectual disability, or congenital malformations in different types of CDG and decreasing sensitivity of screening might be responsible for the CDG cases remaining undiagnosed until adulthood.

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Spontaneous splenic rupture is a known, but rare and possibly fatal, complication of different infectious diseases. We present a case of a 38-year-old male patient who presented with fever, icterus and spontaneous splenic rupture after a visit to Vietnam and discuss the differential diagnosis of splenic rupture in ill returned travellers.

Review question / Objective: To summarize the existing literature on point-of-care ultrasound in dyspnea, nontraumatic hypotension, and shock. Condition being studied: Patients with dyspnea, nontraumatic hypotension, and shock who were assessed using point-of-care ultrasound. Information sources: The electronic databases PubMed and Embase were searched. In addition we reviewed the reference lists of included papers.