Hematopoietic stem cell transplantation in a patient with osteopetrosis and mutation in CLCN7: long-term follow-up / Trasplante de células progenitoras hematopoyéticas en un paciente con osteopetrosis y mutación en CLCN7: seguimiento a largo plazo

Abstract Background: Osteopetrosis is a rare hereditary bone dysplasia characterized by insufficient osteoclast activity that results in increased bone mineral density. Hematopoietic stem cell transplantation (HSCT) can reverse skeletal abnormalities and restore hematopoiesis. Case report: We present the case of a 3-year and 2-month-old male patient with the diagnosis of osteopetrosis. The patient underwent allogeneic HSCT (Allo-HSCT) using 100% compatible bone marrow from a related donor and received a myeloablative conditioning regimen and a CD34 cell dose (4.7 × 107/kg). In the early post-transplant, frequent complications such as pneumonitis, hypercalcemia, and hyperphosphatemia ocurred. With a suitable granulocytic graft and chimerism of 100%, it was considered a successful transplant. However, the patient showed a delayed platelet graft treated with a platelet-stimulating factor for 6 months. The patient is currently disease-free, outpatient follow-up, with no data on graft-versus-host disease, and no progressive neurological damage. Conclusions: Osteopetrosis is a childhood disease that requires clinical suspicion and early diagnosis. HSCT is necessary at an early age to prevent disease progression and sensorineural, hematological, and endocrinological functions damage that can lead to death.

Resumen Introducción: La osteopetrosis es una displasia ósea hereditaria poco común, caracterizada por una actividad osteoclástica deficiente que aumenta la densidad mineral ósea. Se considera que el trasplante de células progenitoras hematopoyéticas (TCPH) puede revertir las anormalidades esqueléticas y restaurar la hematopoyesis. Caso clínico: Se presenta el caso de un paciente de sexo masculino, de 3 años y 2 meses de edad, con diagnóstico tardío de osteopetrosis. Se realizó un TCPH alogénico de donador relacionado 100% compatible con médula ósea. Se utilizaron un régimen de acondicionamiento mieloablativo y una dosis celular de CD34 de 4.7 × 107/kg de peso. En el postrasplante temprano, el paciente desarrolló complicaciones como neumonitis, hipercalcemia e hiperfosfatemia. Con un injerto granulocítico adecuado y quimerismo del 100% se consideró un trasplante exitoso. Sin embargo, el paciente presentó retraso en el injerto plaquetario, por lo que se administró factor estimulante de plaquetas por 6 meses. Actualmente el paciente se encuentra libre de enfermedad, en seguimiento ambulatorio, sin datos de enfermedad del injerto contra el hospedero y con pruebas de neurodesarrollo sin deterioro neurológico progresivo. Conclusiones: La osteopetrosis es una enfermedad infantil que requiere una sospecha clínica y un diagnóstico temprano, ya que es necesario un TCPH a corta edad como tratamiento para evitar la progresión de la enfermedad y el deterioro de las funciones neurosensoriales, hematológicas y endocrinológicas que puede derivar en la defunción del paciente.

Hematopoietic stem cell transplantation in a patient with osteopetrosis and mutation in CLCN7: long-term follow-up.

INTRODUCTION: Osteopetrosis is a rare hereditary bone dysplasia characterized by insufficient osteoclast activity that results in increased bone mineral density. Hematopoietic stem cell transplantation (HSCT) can reverse skeletal abnormalities and restore hematopoiesis. CLINICAL CASE: We present the case of a 3-year and 2-month-old male patient with the diagnosis of osteopetrosis. The patient underwent allogeneic HSCT (Allo-HSCT) using 100% compatible bone marrow from a related and received a myeloablative conditioning regimen and a CD34 cell dose (4.7 × 107/kg). In the early post-transplant, frequent complications such as pneumonitis, hypercalcemia, and hyperphosphatemia ocurred. With a suitable granulocytic graft and chimerism of 100%, it was considered a successful transplant. However, the patient showed a delayed platelet graft treated with a platelet-stimulating factor for 6 months. The patient is currently disease-free, outpatient follow-up, with no data on graft-versus-host disease, and no progressive neurological damage. CONCLUSION: Osteopetrosis is a childhood disease that requires clinical suspicion and early diagnosis. HSCT is necessary at an early age to prevent disease progression and sensorineural, hematological, and endocrinological functions damage that can lead to death.