Iordanis Papadopoulos1, Evangelia Bountouvi1, Achilleas Attilakos2, Evangelia Gole1, Argirios Dinopoulos1, Melpomeni Peppa3, Polyxeni Nikolaidou1, Anna Papadopoulou1. 1. Third Department of Pediatrics, National and Kapodistrian University of Athens, "Attikon" University General Hospital, Athens, Greece. 2. Third Department of Pediatrics, National and Kapodistrian University of Athens, "Attikon" University General Hospital, Athens, Greece. attilakos@hotmail.com. 3. Second Department of Internal Medicine, Research Institute and Diabetes Center, National and Kapodistrian University of Athens, "Attikon" University General Hospital, Athens, Greece.
Abstract
Osteoporosis-pseudoglioma syndrome (OPPG) is a rare autosomal-recessive disorder, characterized by severe osteoporosis and early-onset blindness. Loss of function mutations in the gene encoding low-density lipoprotein receptor-related protein 5 (LRP5) have been established as the genetic defect of the disease. We report the clinical and genetic evaluation of ten OPPG cases in eight related nuclear families and their close relatives. Bone mineral density (BMD) in OPPG patients was assessed by dual-energy X-ray absorptiometry (DXA). Genotyping of LRP5 gene and targeted detection of index mutation were performed by DNA direct sequencing. Four patients were introduced to bisphosphonates. Mutational screening of LRP5 gene revealed the c.2409_2503+79del deletion in homozygous state, expected to result in a truncated protein. Among 44 members of the pedigree, 10 (22%) were identified homozygous and 34 (59%) heterozygous for this mutation. All patients had congenital blindness and 7 of them had also impaired bone mineral density. Four of them received bisphosphonates and responded with decreased bone pain and improvement in BMD; however, 3 patients presented with one fracture during treatment. Conclusion: The current study presents the molecular and clinical profiles of 10 new OPPG cases, being part of an extended pedigree. Patients who received bisphosphonate treatment responded well with increase in their BMD, though fractures occurred during therapy. What is known: • OPPG syndrome is a rare genetic disorder characterized by congenital blindness and juvenile osteoporosis. • Loss of function mutations in the gene encoding low-density lipoprotein receptor-related protein 5 (LRP5) is the genetic defect of the disease. What is new: • Genetic and clinical phenotype of 10 new OPPG patients. • The ten new OPPG patients presented with phenotypical variability in osseous manifestations.
Osteoporosis-pseudoglioma syndrome (OPPG) is a rare autosomal-recessive disorder, characterized by severe osteoporosis and early-onset blindness. Loss of function mutations in the gene encoding low-density lipoprotein receptor-related protein 5 (LRP5) have been established as the genetic defect of the disease. We report the clinical and genetic evaluation of ten OPPG cases in eight related nuclear families and their close relatives. Bone mineral density (BMD) in OPPG patients was assessed by dual-energy X-ray absorptiometry (DXA). Genotyping of LRP5 gene and targeted detection of index mutation were performed by DNA direct sequencing. Four patients were introduced to bisphosphonates. Mutational screening of LRP5 gene revealed the c.2409_2503+79del deletion in homozygous state, expected to result in a truncated protein. Among 44 members of the pedigree, 10 (22%) were identified homozygous and 34 (59%) heterozygous for this mutation. All patients had congenital blindness and 7 of them had also impaired bone mineral density. Four of them received bisphosphonates and responded with decreased bone pain and improvement in BMD; however, 3 patients presented with one fracture during treatment. Conclusion: The current study presents the molecular and clinical profiles of 10 new OPPG cases, being part of an extended pedigree. Patients who received bisphosphonate treatment responded well with increase in their BMD, though fractures occurred during therapy. What is known: • OPPG syndrome is a rare genetic disorder characterized by congenital blindness and juvenile osteoporosis. • Loss of function mutations in the gene encoding low-density lipoprotein receptor-related protein 5 (LRP5) is the genetic defect of the disease. What is new: • Genetic and clinical phenotype of 10 new OPPG patients. • The ten new OPPG patients presented with phenotypical variability in osseous manifestations.
Authors: Mohamed S Abdel-Hamid; Rasha M Elhossini; Ghada A Otaify; Sherif F Abdel-Ghafar; Mona S Aglan Journal: Osteoporos Int Date: 2022-02-01 Impact factor: 4.507
Authors: Silvia Ciancia; Rick R van Rijn; Wolfgang Högler; Natasha M Appelman-Dijkstra; Annemieke M Boot; Theo C J Sas; Judith S Renes Journal: Eur J Pediatr Date: 2022-04-06 Impact factor: 3.860