ESPE Abstracts

Background: Raine syndrome (RS) also known as lethal osteosclerotic bone dysplasia, is a rare autosomal recessive bone disorder. Most of patients with RS die within the first days or weeks of life due to pulmonary hypoplasia. The causative gene FAm²0C is located on chromosome 7p22.3. FAm²0C is one of the genes that regulate phosphate production. Here, we present a case of RS with hypophosphatemic rickets and a new mutation in FAm²0C gene.

Case Report: A seven-year-old girl who had recurrent tooth extractions was referred to our clinic for possible underlying bone disease. Her past history revealed that she had been operated for choanal atresia, cleft palate and atrial septal defect, and bowing of her legs after the age of one. According to his family history, our patient was the fifth child of consanguineous parents and her cousin had similar findings. Physical examination at admission revealed a short stature girl (height sds -2.07) with facial dysmorphism (hypertelorism, exophthalmos, high palate, flattened nasal root, and anteverted ears), odontodysplasia, craniosynostosis, and o-bain deformity. On laboratory; serum calcium level was 9.7mg/dL, phosphorus 2.7mg/dL, alkaline phosphatase 400U/L, parathormone 187ng/l, 25 (OH) D 24.2ng/ml. Tubular reabsorption of phosphate was 92%. There was a minimal metaphysical fraying on x-ray of the knees, no apparent osteosclerosis was seen in the radiographs. Brain MRI showed a Chiari malformation. Based on the clinical and laboratory findings, a diagnosis of hypophosphatemic rickets was made and oral phosphate and calcitriol treatments were started. Raine syndrome was considered due to her additional dysmorphic features, and then a new homozygous mutation was established in the FAm²0C gene.

Conclusions: The clinical features of non-lethal forms of RS are extremely heterogeneous. The present case shows the phenotypic features of Raine syndrome who had a new mutation of FAm²0C gene. RS should be considered especially in the differential diagnosis of patients with hypophosphatemia and odontodysplasia. Because of the small number of reported cases, little evidence of life expectancy and clinical outcome in non-lethal RS.