title: Diagnostic dilemma: osteopetrosis with superimposed rickets causing neonatal hypocalcemia.
abstract: Osteopetrosis is a rare genetic condition of reduced osteoclastic bone resorption which causes defective bone remodeling and skeletal sclerosis during growth, having effects on many organs and tissues. Mutation of T-cell immune regulator 1 (TCRG1) gene is the most common genetic defect leading to osteopetrosis, with poor prognosis. The autosomal recessive form presents in the infantile period (also known as malignant infantile osteopetrosis--MIOP), and is characterized by fractures, short stature, hepatosplenomegaly, compressive neuropathies, hypocalcemia and pancytopenia. Being a rare disease with non-specific clinical manifestations, the diagnosis is difficult and usually delayed. Rickets is a characteristic feature of MIOP which results from the defect in osteoclasts to provide a normal Ca/P balance resulting in the poor mineralization of the osteoid. Various treatment options have been suggested for osteopetrosis, but hematopoietic stem cell transplantation still remains the only curative treatment option presently. The authors report the case of a 46-day-old girl with late-onset neonatal hypocalcemia and rickets that was later diagnosed as osteopetrosis. This case report emphasizes that infantile osteopetrosis is an important cause of neonatal hypocalcemia. As irreversible complications develop within the first months of life, immediate diagnosis and early intervention are crucial and may be life-saving.
authors: Department of Pediatric Metabolism and Nutrition, Gazi University, Ankara, Turkey mabolgac@yahoo.com.
authors: Asburçe
authors: A
authors: Olgaç
authors: Department of Pediatric Metabolism and Nutrition, Gazi University, Ankara, Turkey.
authors: Leyla
authors: L
authors: Tümer
authors: Department of Radiology, Gazi University, Ankara, Turkey.
authors: Öznur
authors: Ö
authors: Boyunağa
authors: Department of Pediatrics, Gazi University, Ankara, Turkey.
authors: Metehan
authors: M
authors: Kızılkaya
authors: Department of Pediatric Metabolism and Nutrition, Gazi University, Ankara, Turkey.
authors: Alev
authors: A
authors: Hasanoğlu
mesh_terms: D050071:Bone Density Conservation Agents / Q000627:therapeutic use; D002117:Calcitriol / Q000627:therapeutic use; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000150:complications*; D007223:Infant; D010022:Osteopetrosis / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy; D012279:Rickets / Q000150:complications*; D016896:Treatment Outcome
chemical_list: D050071:Bone Density Conservation Agents; D002117:Calcitriol
keywords: hypocalcemia; osteopetrosis; osteosclerosis; rickets