Background and Objectives: Uric acid (UA) and the markers of mineral bone metabolism and inflammation are commonly altered in patients with chronic kidney disease (CKD) and are associated with the risk of cardiovascular complications and death. Studies point to a link between high serum UA and mineral bone homeostasis and inflammation, but controversy remains. The aim of this study was to evaluate the relationship between UA levels and mineral bone metabolism and inflammation biomarkers in a sample of Mexican patients with CKD 3a–5. Materials and Methods: This cross-sectional study included 146 Mexican patients with CKD 3a–5. In addition, 25 healthy subjects were included in the study with the aim of generating reference data for comparisons. Metabolic parameters including UA serum concentrations, mineral bone metabolism (parathormone (PTH), fibroblast growth factor 23 (FGF23), calcium, and phosphate), and inflammation (interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α)) biomarkers were measured in all of the samples and compared as a function of the estimated glomerular function rate (eGFR) or UA levels. Results: Intact PTH, FGF23, and cytokines were higher in advanced CKD stages. Patients with hyperuricemia had significantly higher values of FGF23 and TNF-α compared with those without hyperuricemia. The eGFR was found to be significantly and negatively correlated with all markers. Uric acid was significantly correlated with phosphate, iPTH, FGF23, and TNF-α, whereas iPTH was significantly correlated with FGF23, TNF-α, and FGF23. Finally, a multivariate analysis confirmed the relationship of eGFR with all the tested biomarkers, as well as other relationships of iPTH with UA and TNF-α and of FGF23 with UA and TNF-α. Conclusions: This study supports the relationship between uric acid and levels of mineral bone metabolism and inflammation biomarkers in patients with CKD at middle to advanced stages. In the follow-up of patients with CKD, monitoring and controlling UA levels through nutritional or pharmacological interventions could help in the prevention of alterations related to mineral bone metabolism.

Cartilage-hair hypoplasia (CHH) is a rare autosomal recessive skeletal dysplasia caused by variants in RMRP (RNA component of mitochondrial RNA processing endoribonuclease), which encodes a non-coding RNA. Despite its well-established clinical and molecular spectrum in some populations, data from Mexico remain limited. We report eight patients from seven unrelated families with CHH. Clinical and radiographic findings were assessed, and RMRP was analyzed by polymerase chain reaction and Sanger sequencing. All patients exhibited disproportionate short stature; prenatal long-bone shortening and short stature at birth occurred in 50%. Radiographs showed widened long bones and metaphyseal dysplasia in all patients. Extraskeletal manifestations were observed in four patients, each with a distinct feature: immunodeficiency, anemia, Hirschsprung disease, or lymphopenia. RMRP variants were identified in all patients, comprising two homozygous and six compound heterozygous genotypes. Eight variants were detected: three pathogenic (n.6C>T, n.147G>A, and n.72A>G), two likely pathogenic (n.127C>T and n.125C>T), two variants of uncertain significance (n.128G>C and n.215C>T), and a novel promoter deletion (n.-39_-19del) encompassing the RMRP TATA box, classified as likely pathogenic according to the ClinGen RMRP variant interpretation specifications (GN088, Version 1.3). This study expands the clinical and molecular spectrum of CHH in the Mexican population and provides additional evidence for RMRP variant interpretation.