Novel Variant in the USP9X Gene Is Associated with Congenital Heart Disease in a Male Patient: A Case Report and Literature Review.

Introduction: The X-chromosomal USP9X gene encodes a deubiquitylating enzyme involved in protein turnover and TGF-ß signaling during fetal and neuronal development. USP9X variants in females are primarily associated with complete loss-of-function (LOF) alleles, leading to neurodevelopmental delay and intellectual disability, as well as a wide range of congenital anomalies. In contrast, USP9X missense variants in males often result in partial rather than complete LOF, specifically affecting neuronal migration and development. USP9X variants in males are associated with intellectual disability, behavioral disorders, global developmental delay, speech delay, and structural CNS defects. Facial dysmorphisms are found in almost all patients. Case Presentation: We report the case of an Italian boy presenting dysmorphism, intellectual disability, structural brain anomalies, and congenital heart disease. Using next-generation sequencing analysis, we identified a hemizygous de novo variant in the USP9X gene (c.5470A>G, p.Met1824Val) that was never reported in the literature. Conclusion: We provide an overview of the available literature on USP9X variants in males, in order to further expand the genotypic and phenotypic landscape of male-restricted X-linked mental retardation syndrome. Our findings confirm the involvement of USP9X variants in neuronal development and corroborate the possible association between the novel USP9X variant and congenital heart malformation.

Food Habits and Lifestyle in Hyperphenylalaninemia Patients: Should These Be Monitored?

Studies on Hyperphenylalaninemia (HPA) patients are scarce and primarily focused on neurocognitive outcomes compared to PKU patients. In this study, we characterized the food habits and lifestyle of HPA patients compared with healthy peers. We performed a cross-sectional survey of a cohort of 30 patients (13 males, median age/range: 7.9; 2.2-16.7 years) and 28 controls (8 males, median age/range: 7.9; 2.1-16.7 years). Anthropometric parameters, food and nutrient intakes, and level of physical activity were assessed. Food neophobia, eating disorders, and body image perception was investigated by specific tests. Patients showed greater selectivity in the choice of foods than controls, preferring products with lower protein content (p-value: 0.03) and avoiding associating multiple protein and carbohydrate sources. A comparable tendency to distrust new foods emerged without elements suggestive of eating disorders. Patients had higher image dissatisfaction than peers (p-value: 0.01). This group of patients manifested more selective eating habits and worse body image acceptance. A regular evaluation of these aspects in these patients may result in a more effective follow-up of this disorder. More studies are needed to confirm these findings.

Long-term continuous N-carbamylglutamate treatment in frequently decompensated propionic acidemia: a case report.

BACKGROUND: Propionic acidemia is a rare autosomal recessive inherited metabolic disorder that can inhibit the synthesis of N-acetylglutamate, the obligatory activator in urea synthesis, leading to hyperammonemia. N-carbamylglutamate ameliorates hyperammonemia in decompensated propionic acidemia. The effects of long-term continuous N-acetylglutamate administration in such patients are unknown. We report our clinical experience with continuous administration of N-acetylglutamate for 6 years in a patient with propionic acidemia frequently presenting with hyperammonemia. CASE PRESENTATION: A male Caucasian patient with frequently decompensated propionic acidemia and hyperammonemia was admitted 78 times for acute attacks during the first 9 years of his life. Continuous daily treatment with oral N-carbamylglutamate 100 mg/kg (50 mg/kg after 6 months) was initiated. During 6 years of treatment, he had a significant decrease in his mean plasma ammonia levels (75.7 µmol/L vs. 140.3 µmol/L before N-carbamylglutamate therapy, p < 0.005 [normal range 50-80 µmol/L]) and fewer acute episodes (two in 6 years). CONCLUSION: Our results suggest a benefit of N-acetylglutamate administration outside the emergency setting. If this observation is confirmed, future studies should aim to optimize the dosage and explore effects of the dosage requirements on other drugs and on protein tolerance.

Bisphosphonate Treatment in a Patient Affected by MPS IVA with Osteoporotic Phenotype.

Morquio A syndrome (Mucopolysaccharidosis type IVA) (MPS IVA) is a rare inherited metabolic disorder characterized by the defective degradation of keratan sulfate and chondroitin-6-sulfate. Classically, MPS IVA patients present with severe multisystemic involvement and have a short life expectancy. Attenuated forms with clinical features limited to minor skeletal abnormalities and short stature have also been described, sometimes associated to an early-onset osteoporotic phenotype. No treatment with allogenic bone marrow transplantation or gene therapy is currently available for Morquio A syndrome, and enzyme replacement therapy is under evaluation. We report a case of MPS IVA, who manifested tardily attenuated phenotype and significant bone mass reduction, which was treated with a bisphosphonate (BPN), resulting in an improvement of X-ray skeletal aspects and functional bone performance. We suggest that the use of bisphosphonates may be an interesting supportive therapeutic option for Morquio A patients with osteoporotic phenotype, but further studies involving more patients are necessary to confirm our findings.