Uncovering genetic causes of hypophosphatemia.

BACKGROUND: Chronic hypophosphatemia can result from a variety of acquired disorders, such as malnutrition, intestinal malabsorption, hyperparathyroidism, vitamin D deficiency, excess alcohol intake, some drugs, or organ transplantation. Genetic disorders can be a cause of persistent hypophosphatemia, although they are less recognized. We aimed to better understand the prevalence of genetic hypophosphatemia in the population. METHODS: By combining retrospective and prospective strategies, we searched the laboratory database of 815,828 phosphorus analyses and included patients 17-55 years old with low serum phosphorus. We reviewed the charts of 1287 outpatients with at least 1 phosphorus result ≤2.2 mg/dL. After ruling out clear secondary causes, 109 patients underwent further clinical and analytical studies. Among them, we confirmed hypophosphatemia in 39 patients. After excluding other evident secondary causes, such as primary hyperparathyroidism and vitamin D deficiency, we performed a molecular analysis in 42 patients by sequencing the exonic and flanking intronic regions of a panel of genes related to rickets or hypophosphatemia (CLCN5, CYP27B1, dentin matrix acidic phosphoprotein 1, ENPP1, FAM20C, FGFR1, FGF23, GNAS, PHEX, SLC34A3, and VDR). RESULTS: We identified 14 index patients with hypophosphatemia and variants in genes related to phosphate metabolism. The phenotype of most patients was mild, but two patients with X-linked hypophosphatemia (XLH) due to novel PHEX mutations had marked skeletal abnormalities. CONCLUSION: Genetic causes should be considered in children, but also in adult patients with hypophosphatemia of unknown origin. Our data are consistent with the conception that XLH is the most common cause of genetic hypophosphatemia with an overt musculoskeletal phenotype.

Etiology of hypophosphatemia in adults. / Etiología de la hipofosfatemia en el adulto.

Long-term hypophosphatemia, defined by serum phosphorus (P) levels <2.5mg/dL, impairs the development and quality of mineralized tissue of the skeletal, dental, and auditory systems. P homeostasis depends mainly on intestinal absorption and renal excretion. Hypophosphatemia may be due to the redistribution of P to the intracellular space, increased renal losses, or decreased intestinal absorption. Hypophosphatemia can be categorized as acute or chronic, depending on the time course. Most cases, either acute or chronic, are due to acquired causes. However, some chronic cases may have a genetic origin. Accurate and early diagnosis, followed by adequate treatment, is essential to limit its negative effects on the body.

Long-term outcomes in two adult siblings with Fucosidosis - Diagnostic odyssey and clinical manifestations.

Fucosidosis (OMIN# 230000) is a rare lysosomal storage disorder (LSDs) caused by mutations in the FUCA1 gene, leading to alpha-L-fucosidase deficiency; it is inherited as an autosomal recessive trait. Fucosidosis represents a disease spectrum with a wide variety of clinical features, but most affected patients have slow neurologic deterioration. Many patients die young and the long-term clinical outcomes in adult patients are poorly documented. Here, we report the long-term follow up of two Caucasian siblings, a 31-year-old man and 25-year-old woman. We describe the clinical, biochemical, radiological and genetic findings in two siblings affected by Fucosidosis and the differences between them after 19-years follow up. The dermatological features of the younger sibling have been reported previously by Bharati et al. (2007). Both patients have typical features of Fucosidosis, such as learning difficulties, ataxia, and angiokeratomas with differing severity. Case 1 presents severe ataxia with greater limitation of mobility, multiple dysostoses, angiokeratomas on his limbs, retinal vein enlargement and increased tortuosity in the eye and gastrointestinal symptoms. Biochemical analysis demonstrated a deficiency of alpha-fucosidase in leucocytes. Case 2 has a greater number of angiokeratomas and has suffered three psychotic episodes. The diagnosis of Fucosidosis was confirmed in cultured skin fibroblast at the age of 12 years. Molecular analysis of the FUCA1 gene showed a heterozygous mutation c.998G > A p.(Gly333Asp), with a pathogenic exon 4 deletion in the other allele in both patients. Conclusion. Fucosidosis presents a wide clinical heterogeneity and intrafamilial variability of symptoms. Psychosis and gastrointestinal symptoms have not been reported previously in Fucosidosis.

Prognostic Factors Associated with Acute Heart Failure in Patients Admitted for COVID-19: Analysis of the SEMI-COVID-19 Registry.

INTRODUCTION: Since the beginning of the COVID-19 pandemic in March 2020, an intimate relationship between this disease and cardiovascular diseases has been seen. However, few studies assess the development of heart failure during this infection. This study aims to determine the predisposing factors for the development of heart failure (HF) during hospital admission of COVID-19 patients. METHODOLOGY: A retrospective and multicenter study of patients with HF admitted for COVID-19 in 150 Spanish hospitals (SEMI-COVID-19 Registry). A bivariate analysis was performed to relate the different variables evaluated in patients developing heart failure during hospital admission. A multivariate analysis including the most relevant clinical variables obtained in bivariate analyses to predict the outcome of heart failure was performed. RESULTS: A total of 16.474 patients hospitalized for COVID-19 were included (57.5% men, mean age 67 years), 958 of them (5.8%) developed HF during hospitalization. The risk factors for HF development were: age (odds ratio [OR]): 1.042; confidence interval 95% (CI 95%): 1.035-1.050; p < 0.001), atrial fibrillation (OR: 2.022; CI 95%: 1.697-2.410; p < 0.001), BMI > 30 kg/m2 (OR: 1.460 CI 95%: 1.230-1.733; p < 0001), and peripheral vascular disease (OR: 1.564; CI 95%: 1.217-2.201; p < 0.001). Patients who developed HF had a higher rate of mortality (54.1% vs. 19.1%, p < 0.001), intubation rate (OR: 2,36; p < 0.001), and ICU admissions (OR: 2.38; p < 0001). CONCLUSIONS: Patients who presented a higher risk of developing HF were older with cardiovascular risk factors. The risk factors for HF development were age, atrial fibrillation, obesity, and peripheral vascular disease. In addition, patients who developed HF more frequently required to be intubated or admitted to the ICU.