ESPE Abstracts

Background: Mutations in genes encoding type 1 procollagen (T1PC) and proteins responsible for posttranslational modifications of the T1PC heterodimer may result in brittle bone disorder osteogenesis imperfecta (OI). FKBP65 is a known chaperone for type I procollagen and encoded by FKBP10. Autosomal-recessively inherited epidermolysis bullosa simplex and moderately severe OI caused by FKBP10 mutation reported in consanguineous Turkish and Mexican families.

Objective and hypotheses: Our aim is to demonstrate new case with FKBP10 mutation.

Methods: 19^5/12 years-old male admitted with multiple skin lesions and recurrent bone fractures since birth. His parents were first cousins. He was born with skin bilsters on his body. His left arm was broken during delivery and until today he had recurrent long bone and vertebral fractures. At 10 years-old, he was diagnosed as OI and alendronat treatment started; however patient did not use the drug. He was untreated for a period of 9 years and had multiple fractures in long bones and vertebrae.

Results: On the admission his weight was15.9 kg, length was 87 cm. He had greyish-white sclera and normal teeth. Diffuse bullous erythematous lesion was determined on extensor surface of both extremities and thorax. Severe kyphoscoliosis and multiple deformities in both extremities due to recurrent fractures were determined. He was early-pubertal stage. Skin biopsy was consisting with bullous dermatitis. BMD-Z score was −6.7 (0.340 g/cm³) on lumbar vertebrae 1–4. Audiometric examination revealed mild mixt type sensorineural hearing lost. Pamidronat-sodium therapy was started as 1 mg/kg per day for 3-days (3-monthly). FKBP10 gene mutation analysis was performed in all family members. Patient has homozygous p.Met107-Leu117del mutation in FKBP10. Parents has heterozygous this mutation.

Conclusion: Homozygosity for a 33 bp deletion (c.321_353del) in FKBP10 is resulted in deletion of 11 amino acids (p.Met107-Leu117del). Disrupted type 1 collagen was synthesized and caused severe skin and bone disorders in patients.

: