Gursev S Dhaunsi

Introduction: Mitochondrial dysfunction and Toll-like receptors (TLRs) are commonly associated with oxidative stress and apoptotic cell death in metabolic disorders; however, their roles in Classical Galactosemia remain largely unexplored. This study examined the activities of key mitochondrial enzymes, as well as the gene expression of peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) and Toll-like receptor-2, under hypergalactosemic or hyperglycemic conditions in fibroblast cultures. Methods: Confluent fibroblast cultures were established from the post-circumcision skin of 2–3-day-old healthy neonates. Next, these fibroblast cultures were treated with D-Galactose (D-Gal, 0–20 mM), galactose-1-phosphate (Gal-1-P, 0–5 mM), or “high glucose” (HG, 25 mM). Peripheral blood mononuclear cells (PBMCs) were isolated from galactosemia patients and control subjects. Activities of medium-chain acyl-CoA dehydrogenase (MCAD), cytochrome c oxidase (CcO), and carnitine palmitoyltransferase-1 (CPT-1) were analyzed in cell homogenates and in PBMCs of both patients and controls. ATP production and malondialdehyde (MDA) levels in fibroblasts were measured using commercial kits. In addition, PGC-1α and TLR-2 were examined in fibroblast cultures by western blot analysis. Results: D-Gal and Gal-1-P significantly (p < 0.05) reduced the enzyme activities of CPT-1, MCAD, and CcO, with Gal-1-P causing a more pronounced (p < 0.01) effect on CPT-1 compared to the control group. HG had no significant impact on these mitochondrial enzymes. Moreover, mitochondrial enzyme activities were markedly lower in PBMCs from galactosemia patients than from control subjects. Galactose-treated fibroblasts showed elevated TLR-2 levels but unchanged PGC-1α expression compared to control cells. Only Gal-1-P significantly diminished PGC-1α levels, whereas HG, D-Gal, and Gal-1-P significantly upregulated the expression of TLR-2. Conclusion: These findings suggest that galactosemia pathogenesis involves Gal-1-P–mediated mitochondrial dysfunction and elevated TLR-2 gene expression.

Introduction: Mucopolysaccharidosis type I (MPSI) is an autosomal recessive lysosomal storage disorder characterized by deficient or absent α-L-iduronidase (IDUA) enzyme activity due to pathogenic variants in IDUA gene. Early treatment with hematopoietic stem cell transplantation and/or enzyme replacement therapy is associated with improved outcomes in this progressive multisystem disease. The diagnosis is usually delayed due to late presentation and nonspecific symptoms resulting in high morbidity and mortality. The incidence of MPSI in US is estimated to be 0.26:100,000, however, it is unknown in Kuwait. This pilot study was undertaken to screen MPSI in all Kuwaiti neonates born at Farwaniya Hospital over a period of 12-months. This study examined the incidence of MPSI in a major center in Kuwait for inclusion in the national newborn screening program to enable its early detection and adequate treatment. Methods: All Kuwaiti neonates born at Farwaniya Hospital, Kuwait from December 2021 to December 2022, were screened for MPSI. The screening consisted of determining IDUA enzyme activity in dried blood spots (DBS)-derived samples by Tandem Mass Spectrometry. A follow-up genetic analysis of IDUA gene is planned to screen the cases with diminished IDUA enzyme activity as second-tier testing. Results: A total of 618 newborns, including 331 (54%) males and 287 (46%) females, were screened. Twenty of them had deficient IDUA enzyme activity but showed negative genetic testing for IDUA. However, we have diagnosed one additional female baby with MPSI, who belonged to Farwaniya Hospital, but the parents chose to deliver in a private hospital. She presented at age three months with recurrent upper airway infections, snoring and extensive Mongolian spots. The molecular study revealed previously reported pathogenic nonsense variant in IDUA c.1882C>T; p.(Arg628Ter), associated with severe phenotype. That being included, MPSI is estimated to be about 0.3% among tested females and 0.2% of all screened cases in Kuwait. Conclusion: Our study is the first to evaluate the incidence of MPSI in Kuwait. Given the single center, small number of screened babies and the short study duration thus far, it is premature to calculate the incidence of MPSI. It is anticipated that as the study continues and more infants are examined, we would be able to estimate the incidence of this disease in our population correctly. Further studies including screening newborns in all maternity hospitals in Kuwait are needed to calculate the actual incidence of MPSI. Our data supports including MPSI in national newborn screening program to allow early initiation of treatment and thus improve disease outcome.