Impact of genetic and non-genetic factors on phenotypic diversity in NBAS-associated disease.

Biallelic pathogenic variants in neuroblastoma-amplified sequence (NBAS) cause a pleiotropic multisystem disorder. Three clinical subgroups have been defined correlating with the localisation of pathogenic variants in the NBAS gene: variants affecting the C-terminal region of NBAS result in SOPH syndrome (short stature, optic atrophy, Pelger-Huët anomaly), variants affecting the Sec 39 domain are associated with infantile liver failure syndrome type 2 (ILFS2) and variants affecting the ß-propeller domain give rise to a combined phenotype. However, there is still unexplained phenotypic diversity across the three subgroups, challenging the current concept of genotype-phenotype correlations in NBAS-associated disease. Therefore, besides examining the genetic influence, we aim to elucidate the potential impact of pre-symptomatic diagnosis, emergency management and other modifying variables on the clinical phenotype. We investigated genotype-phenotype correlations in individuals sharing the same genotypes (n = 30 individuals), and in those sharing the same missense variants with a loss-of-function variant in trans (n = 38 individuals). Effects of a pre-symptomatic diagnosis and emergency management on the severity of acute liver failure (ALF) episodes also were analysed, comparing liver function tests (ALAT, ASAT, INR) and mortality. A strong genotype-phenotype correlation was demonstrated in individuals sharing the same genotype; this was especially true for the ILFS2 subgroup. Genotype-phenotype correlation in patients sharing only one missense variant was still high, though at a lower level. Pre-symptomatic diagnosis in combination with an emergency management protocol leads to a trend of reduced severity of ALF. High genetic impact on clinical phenotype in NBAS-associated disease facilitates monitoring and management of affected patients sharing the same genotype. Pre-symptomatic diagnosis and an emergency management protocol do not prevent ALF but may reduce its clinical severity.

Biotinidase deficiency: What have we learned in forty years?

BACKGROUND: Biotinidase deficiency (BD) is an autosomal recessively inherited disorder that was first described in 1982. Forty years after its first description, we compiled available clinical data on BD with the aim of generating a more comprehensive picture of this condition. METHODS: A systematic search strategy was performed in relevant databases without limits for publication date or languages. We screened 3966 records and included 144 articles reporting individuals with BD and their clinical presentation as well as the outcomes, when available. RESULTS: This study included 1113 individuals with BD. More than half (51.5%) of these individuals were diagnosed by newborn screening, 43.3% in presence of clinical symptoms and 5.2% due to family screening. We grouped symptomatic individuals into four main clinical presentations: neonatal-onset (<1 month; 7.9%), early childhood-onset (<2 years; 59.2%), juvenile-onset (2-16 years; 25.1%) and adult-onset (>16 years; 7.7%). BD affected five main organ systems: nervous system (67.2%), skin (53.7%), eye (34.4%), auditory (26.9%) and respiratory system (17.8%). Involvement was mainly multisystemic (82.2%) of individuals, whereas isolated system presentation was seen in only 17.2% of individuals. When reported, metabolic acidosis was present in 42.4% of symptomatic individuals and characteristic abnormal organic acid metabolites were found in 57.1%. Biotin treatment led to clinical stability or improvement in 89.2% of individuals. 1.6% of reported individuals with BD died due to non-availability of treatment or late diagnosis. CONCLUSION: Newborn screening has had a major positive impact on the outcome of many individuals with BD. However, undiagnosed and non-treated BD remains a health concern. Given the risk of mortality or complications associated with late or missed diagnosis if newborn screening is not available, a trial of biotin should be considered in undiagnosed infants and adults exhibiting suspected clinical signs. Enzymatic activity and/or analysis of genetic variants can readily confirm the diagnosis of BD.

[Is ketogenic diet effective against cancer ?] / Le régime cétogène : efficace contre le cancer ?

The ketogenic diet, which consists of reduced carbohydrate intake and increased fat intake, is a recognized treatment option for children with intractable epilepsy. This diet is now receiving renewed interest from physicians and researchers because of its potential therapeutic effect in other diseases, such as neurodegenerative diseases, metabolic syndrome or cancer. Since cancer is one of the major public health challenges, complementary approaches to improve the efficacy of standard anti-cancer therapies are the subject of much research. This article reviews the place of the ketogenic diet as a complementary therapy in cancer, the scientific evidence and possible practical aspects of such an approach.

Le régime cétogène vise à réduire l'apport nutritionnel d'hydrates de carbone en augmentant les lipides. Ce régime est une option thérapeutique reconnue, en particulier chez les enfants souffrant d'épilepsie réfractaire. Il fait aujourd'hui l'objet d'un regain d'intérêt de la part des médecins et des chercheurs, en raison de son potentiel effet thérapeutique dans d'autres pathologies comme certaines maladies neurodégénératives, le syndrome métabolique ou même le cancer. Le cancer étant l'un des grands défis de santé publique, les approches complémentaires pour améliorer l'efficacité des thérapies anticancéreuses standards font l'objet de nombreuses recherches. Cet article fait le point sur la place du régime cétogène comme thérapie complémentaire dans le cancer, les évidences scientifiques et les éventuels aspects pratiques d'une telle approche.

Elevated lactate in Mauriac syndrome: still a mystery.

BACKGROUND: The Mauriac syndrome was described in 1930 as a peculiar combination of poorly controlled diabetes mellitus type 1, stunted growth and glycogenic hepatopathy. More recently, lactic acidosis was recognized as an additional feature, often induced by insulin treatment. CASE PRESENTATION: A 17-year old girl known for diabetes type 1A and Mauriac syndrome was admitted to the emergency room with hyperglycemia of > 41 mmol/l without ketoacidosis. Under a standard insulin regimen, hyperglycemia was rapidly corrected but marked hyperlactatemia occurred. CONCLUSIONS: The mechanism of impaired glucose utilization and lactate elevation independent of ketoacidosis in Mauriac syndrome is intriguing. The rarity of Mauriac syndrome and its resemblance to glycogen storage diseases suggest the presence of a specific metabolic or genetic predisposition that remains to be identified.

Cellular circadian period length inversely correlates with HbA1c levels in individuals with type 2 diabetes.

AIMS/HYPOTHESIS: The circadian system plays an essential role in regulating the timing of human metabolism. Indeed, circadian misalignment is strongly associated with high rates of metabolic disorders. The properties of the circadian oscillator can be measured in cells cultured in vitro and these cellular rhythms are highly informative of the physiological circadian rhythm in vivo. We aimed to discover whether molecular properties of the circadian oscillator are altered as a result of type 2 diabetes. METHODS: We assessed molecular clock properties in dermal fibroblasts established from skin biopsies taken from nine obese and eight non-obese individuals with type 2 diabetes and 11 non-diabetic control individuals. Following in vitro synchronisation, primary fibroblast cultures were subjected to continuous assessment of circadian bioluminescence profiles based on lentiviral luciferase reporters. RESULTS: We observed a significant inverse correlation (ρ = -0.592; p < 0.05) between HbA1c values and circadian period length within cells from the type 2 diabetes group. RNA sequencing analysis conducted on samples from this group revealed that ICAM1, encoding the endothelial adhesion protein, was differentially expressed in fibroblasts from individuals with poorly controlled vs well-controlled type 2 diabetes and its levels correlated with cellular period length. Consistent with this circadian link, the ICAM1 gene also displayed rhythmic binding of the circadian locomotor output cycles kaput (CLOCK) protein that correlated with gene expression. CONCLUSIONS/INTERPRETATION: We provide for the first time a potential molecular link between glycaemic control in individuals with type 2 diabetes and circadian clock machinery. This paves the way for further mechanistic understanding of circadian oscillator changes upon type 2 diabetes development in humans. DATA AVAILABILITY: RNA sequencing data and clinical phenotypic data have been deposited at the European Genome-phenome Archive (EGA), which is hosted by the European Bioinformatics Institute (EBI) and the Centre for Genomic Regulation (CRG), ega-box-1210, under accession no. EGAS00001003622.

Hepatosplenomegaly, pneumopathy, bone changes and fronto-temporal dementia: Niemann-Pick type B and SQSTM1-associated Paget's disease in the same individual.

Data from exome sequencing show that a proportion of individuals in whom a genetic disorder is suspected turn out to have not one, but two to four distinct ones. This may require an evolution in our diagnostic attitude towards individuals with complex disorders. We report a patient with splenomegaly, pneumopathy, bone changes and fronto-temporal dementia (FTD). "Sea-blue histiocytes" in his bone marrow pointed to a lysosomal storage disease. Homozygosity for a pathogenic mutation in the SMPD1 gene confirmed Niemann-Pick disease type B (NPD-B). Mild cognitive impairment and abnormal brain FDG PET were consistent with FTD. We initially tried to fit the skeletal and neurologic phenotype into the NPD-B diagnosis. However, additional studies revealed a pathogenic mutation in the SQSTM1 gene. Thus, our patient had two distinct diseases; NPD-B, and Paget's disease of bone with FTD. The subsequent finding of a mutation in SQSTM1 gene ended our struggle to explain the combination of findings by a singular "unifying" diagnosis and allowed us to make specific therapeutic decisions. SQSTM1 mutations have been reported in association with FTD, possibly because of defective autophagy. Bisphosphonates may be beneficial for PDB, but since they are known to inhibit acid sphingomyelinase activity, we refrained from using them in this patient. While the principle of looking for unifying diagnosis remains valid, physicians should consider the possibility of co-existing multiple diagnoses when clinical features are difficult to explain by a single one. Accurate diagnostic work-up can guide genetic counseling but also lead to better medical management.

[Diabetes, cancer and obesity†: unequivocal association]. / Diabète, cancer et obésité†: une relation sans équivoque.

Obesity and type 2 diabetes have a constantly increasing prevalence in industrialized countries, and both are associated with an increased risk of developing certain cancers. The mechanisms that contribute to this association are probably multiple and are based mainly on hormonal and inflammatory changes. In view of this unequivocal relationship, it is necessary to act upstream by optimizing diabetes prevention and cancer screening measures in at-risk populations. This article reviews the epidemiological data, the physiopathological link between these entities and the concrete measures to be applied in clinical practice.

L'obésité et le diabète de type 2 ont une prévalence en constante augmentation dans les pays industrialisés, et tous deux sont associés avec un risque accru de développer certains cancers. Les mécanismes qui contribuent à cette association sont probablement multiples et reposent principalement sur des modifications hormonales et inflammatoires. Face à cette relation sans équivoque, il est nécessaire d'agir en amont en optimalisant les mesures de prévention du diabète et de dépistage du cancer dans les populations à risque. Cet article fait le point sur les données épidémiologiques, le lien physiopathologique entre ces entités ainsi que les mesures concrètes à appliquer en pratique clinique.

[Statin-associated muscle symptoms : Current management in 2018]. / Symptômes musculaires associés aux statines : quelle prise en charge en 2018 ?

Statins are the first line treatment in hyperlipidemia, either in primary or secondary prevention of cardiovascular diseases. One of the most prescribed drug class worldwide, this drug class is often the focus of highly publicized drug controversies. Various adverse effects have been attributed to statins, in particular statin-associated muscle symptoms (SAMS). This condition varies in severity (from frequent isolated myalgia to rare severe myositis, even rhabdomyolysis) and often leads to treatment termination. Because SAMS are a daily challenge in clinical practice, we review here the recent medical literature on this topic and suggest a management strategy to be shared with the patient as an active partner.

Les statines représentent la première ligne de traitement en cas d'hypercholestérolémie, que ce soit en prévention primaire ou secondaire des maladies cardiovasculaires. C'est l'une des classes médicamenteuses les plus prescrites au monde, mais qui fait l'objet de controverses médiatisées. De nombreux effets indésirables ont été attribués à la prise de statines, notamment les symptômes musculaires associés aux statines (SMAS). On relève différents types d'atteinte, d'intensité croissante (de myalgies fréquentes à une myosite sévère mais rare, voire une rhabdomyolyse), pouvant mener à l'arrêt du traitement. Au vu du défi que représentent les SMAS dans la pratique courante ambulatoire, cet article donne au praticien un aperçu de la littérature récente, ainsi qu'une proposition de prise en charge à partager avec le patient.

Clinical presentation and outcome in a series of 32 patients with 2-methylacetoacetyl-coenzyme A thiolase (MAT) deficiency.

2-methylacetoacetyl-coenzyme A thiolase (MAT) deficiency, also known as beta-ketothiolase deficiency, is an inborn error of ketone body utilization and isoleucine catabolism. It is caused by mutations in the ACAT1 gene and may present with metabolic ketoacidosis. In order to obtain a more comprehensive view on this disease, we have collected clinical and biochemical data as well as information on ACAT1 mutations of 32 patients from 12 metabolic centers in five countries. Patients were between 23months and 27years old, more than half of them were offspring of a consanguineous union. 63% of the study participants presented with a metabolic decompensation while most others were identified via newborn screening or family studies. In symptomatic patients, age at manifestation ranged between 5months and 6.8years. Only 7% developed a major mental disability while the vast majority was cognitively normal. More than one third of the identified mutations in ACAT1 are intronic mutations which are expected to disturb splicing. We identified several novel mutations but, in agreement with previous reports, no clear genotype-phenotype correlation could be found. Our study underlines that the prognosis in MAT deficiency is good and MAT deficient individuals may remain asymptomatic, if diagnosed early and preventive measures are applied.

Pulmonary Involvement in Adult Patients with Inborn Errors of Metabolism.

Inborn errors of metabolism (IEM) are rare individually, but taken together, they affect 1 in 1,000 people. Most of the disease becomes apparent at the pediatric age; however, with the identification of late-onset forms, and with improved survival, several of these conditions may be found in adults of all ages. While the lung is not typically a primary site of clinical disease in patients with IEM, in some of them it can be a significantly affected organ with associated severe respiratory complications. Lung involvement can be a late- onset feature of a complex multisystemic disease, but sometimes it can also be the only manifestation of underlying IEM. The aim of this review is to focus on specific IEM associated with lung disease in adults and to provide the reader with an overview of the diagnostic workup, overall disease management, and specific treatments for the respiratory manifestations. Clinical suspicion, early recognition, prompt diagnosis, and appropriate care of the respiratory manifestation are crucial, as they can affect both the life expectancy and the quality of life of these patients.

[Raising the internist's know-how in the field of rare diseases: mitochondrial diseases as an illustrative example]. / L'interniste face aux maladies rares: quand y penser? L'exemple des maladies mitochondriales.

Rare Diseases, defined by a prevalence of less than 1 per 2000 persons, affect 36 million people in Europe, 500 000 in Switzerland, corresponding to 6-8% of the general population. 7000 rare diseases are currently recorded.Mitochondrial diseases are a heterogeneous group of genetic diseases. They are characterized by intracellular failure of energy production and affect predominantly energy-dependent tissues. The clinical presentation is not always suggestive, particularly in adulthood. In order to reach the diagnosis, a prerequisite is to think of them. In this article, we will focus on the clinical aspects of mitochondrial disorders in order to give the internist simple tools on how not to miss those rare diseases in his daily practice.

Les maladies rares, définies par une prévalence égale ou inférieure à 1 pour 2000 personnes, touchent 36 millions de personnes en Europe et 500 000 en Suisse, soit 6 à 8% de la population générale. On en dénombre quelque 7000 actuellement.Les maladies mitochondriales constituent un groupe hétérogène de maladies génétiques. Elles sont liées à des carences de production intracellulaire d'énergie et s'expriment principalement sur les tissus énergie-dépendants. L'expression phénotypique n'est pas toujours spontanément évocatrice, en particulier chez l'adulte. Nous proposons dans cet article une approche centrée sur la clinique des maladies mitochondriales permettant à l'interniste de les évoquer.

[Artificial sweeteners and diabetes: friends or foes?]. / Edulcorants artificiels et diabète: faux amis?

Sugary drinks consumption is associated with increased risk of obesity and type 2 diabetes. Thereby, artificial sweeteners (AS) consumption became increasingly popular and were introduced largely in our diet in order to reduce calorie intake and normalise blood glucose levels without altering our taste for "sweetness". However, the results of published studies on health outcomes secondary to AS intake, including type 2 diabetes risk, are inconsistent. The aim of this article is to focus on the role of AS in glucose homeostasis and diabetes onset.

Overweight and obesity in adult patients with phenylketonuria: a systematic review.

BACKGROUND: Excess weight is a rising concern in patients with phenylketonuria (PKU). It is commonly observed in children and adolescents with PKU; but data on adults are inconsistent. This review aims to summarize available data on excess weight in adult PKU individuals. METHODS: We conducted a systematic search of literature in English, from inception to October 2021, on PubMed and Embase to identify articles on overweight and obesity in adult PKU patients. Prevalence of overweight and obesity, body mass index (BMI) and gender differences were the outcomes of interest. RESULTS: Of 260 articles identified, only 8 fulfilled quality criteria for inclusion after screening of titles, abstracts and full texts. The mean BMI of adult PKU patients in these studies ranged from 26 ± 5.4 to 30.3 ± 1.8 kg/m2. When compared to matched controls, adult PKU patients had higher BMI and higher prevalence of obesity. However, results were inconsistent when PKU adults were compared to the general population. The prevalence of obesity in the included studies varied widely between 4.5% up to 72% in individual studies. Obesity was 2-3 times more frequent in female PKU patients. CONCLUSIONS: Excess weight is frequent in adult PKU patients, especially in females, even if the difference with the general population is debatable. The heterogeneity of the studies makes it difficult to interpret the results and the factors that contribute to obesity. Content of the diet, psychological status, diet-associated disordered eating, patient's social environment and lifestyle are listed as potentials contributors to excess weight in PKU adult population. Further studies are needed to better elucidate this question. In the meantime, weight control and healthy eating habits should be considered in the management and follow-up of these patients.

[Sucrose, glucose, fructose consumption: what are the impacts on metabolic health?]. / Sucrose, glucose, fructose: quels sont les effets des sucres sur la santé métabolique?

There is growing evidence that consumption of added sugars play a role in the recent increase of metabolic diseases: 1) The intake of derived caloric sweeteners has increased in conjunction with rising prevalence of obesity; 2) Epidemiologic data and experimental studies show a positive correlation between sugar, fructose or sweetened beverages consumption and component of the metabolic syndrome. Several questions regarding effect of natural sugars on health are not answered yet, particularly the interactions between sugar intake and environment factors including ethnicity background and physical activity. Only Interventional studies will elucidate if there is a causal relation between sugar intake and metabolic diseases in humans.

[Chronic Fatigue: When to Suspect an Inherited Metabolic Disease?] / Chronische Müdigkeit: Wann liegt der Verdacht auf eine erbliche Stoffwechselerkrankung vor?

Chronic Fatigue: When to Suspect an Inherited Metabolic Disease? Abstract. Chronic fatigue is a non-specific symptom, frequent in outpatient adults' consultations. Persistent physical fatigue of unknown etiology should prompt the search for rare diseases including inherited metabolic disorder (IMD) after elimination of common causes. The main characteristic of chronic fatigue in IMD is its dynamic nature, worsened by circumstances leading to an increased metabolism such as physical exertion, cold, fasting or infection. IMD leading to chronic fatigue are metabolic myopathies, in particular glycogen storage disease affecting muscle, fatty acid oxidation disorders and mitochondrial diseases. The diagnosis is confirmed by specific biochemical and/or molecular analyzes with multidisciplinary management.

[Chronic Fatigue: When to Suspect an Inherited Metabolic Disease?] / Fatigue chronique: quand suspecter une maladie héréditaire du métabolisme?

Chronic Fatigue: When to Suspect an Inherited Metabolic Disease? Abstract. Chronic fatigue is a non-specific symptom, frequent in outpatient adults' consultations. Persistent physical fatigue of unknown etiology should prompt the search for rare diseases including inherited metabolic disorder (IMD) after elimination of common causes. The main characteristic of chronic fatigue in IMD is its dynamic nature, worsened by circumstances leading to an increased metabolism such as physical exertion, cold, fasting or infection. IMD leading to chronic fatigue are metabolic myopathies, in particular glycogen storage disease affecting muscle, fatty acid oxidation disorders and mitochondrial diseases. The diagnosis is confirmed by specific biochemical and/or molecular analyzes with multidisciplinary management.

Résumé. La fatigue chronique est un symptôme peu spécifique, fréquent en consultation ambulatoire de l'adulte. Une fatigue physique persistante, d'étiologie indéterminée après élimination des causes courantes, doit faire évoquer des maladies rares telles que les erreurs innées du métabolisme (EIM). La principale caractéristique de la fatigue chronique dans les EIM est son caractère dynamique, aggravée par les situations entrainant une augmentation du métabolisme telles que l'effort physique, le froid, le jeûne ou un stress biologique. Devant de tels indices cliniques, il est important d'entreprendre une démarche diagnostique orientée permettant d'identifier les patients susceptibles d'avoir une EIM afin de les orienter vers un centre spécialisé. Les EIM entrainant une fatigue chronique sont les myopathies métaboliques, notamment les glycogénoses musculaires, les troubles de la béta-oxydation des acides gras et les maladies mitochondriales. Des analyses biochimiques et/ou moléculaires spécifiques permettent de poser le diagnostic et de mettre en place une prise en charge pluridisciplinaire.