Schimke immuno-osseous dysplasia (SIOD) is one of the rare causes of steroid-resistant nephrotic syndrome. Extra-renal symptoms of this autosomal recessive disease include spondyloepiphyseal dysplasia, disproportional growth failure and defective cellular immunity. Kidney transplantation (KT) is indicated in these patients when their kidney problems progress to end-stage renal disease (ESRD). Due to the rarity of this condition, clinical course of SIOD after KT is not well known yet. Here we present our experience of SIOD after KT.
Since 2014 three children with focal segmental glomerulosclerosis (FSGS) confirmed by biopsy were diagnosed as SIOD through genetic analysis. Onset age of proteinuria was 7, 5, 3 years, respectively. All of them had disproportional growth failure and typical facial feature. They reached ESRD in about two years after diagnosis of proteinuria. At their age of 9, 7, 9 years, these patients had living donor KT from their parents. After KT they suffered from multiple infections. Case 1 had PCP pneumonia requiring ventilator care 2 months after KT, then in 3 months disseminated adenovirus infection occurred along with CMV, EBV, and JC virus infection. The patient succumbed to the infection in 2 months despite aggressive management. Case 2 had CMV infection and PCP pneumonia after 3 months of KT. She suffered from skin infection and otitis. Case 3 suffered from respiratory failure due to CMV infection after 5 months of KT. Recurrent hospitalization was required due to various infections. Allograft has survived for 3.5 years in case 3 despite low-dose tacrolimus single medication (< 5ng/mL), but case 1 lost his graft function along with disseminated adenovirus infection. Case 2 had graft failure after 5 years of KT from acute rejection, probably due to insufficient dosage of tacrolimus and poor compliance. As Extra-renal presentation case 1 had renal vein thrombosis extended to IVC and pulmonary hypertension before KT, lowering his oxygen saturation to 80-90% in room air. Case 2 had severe developmental dysplasia of the hip requiring orthopedic surgery at the age of 5. She had sitting height and leg length ratio of 0.96, vertebral flattening and lordosis on spine x-ray suggesting spondyloepiphyseal dysplasia. After KT she suffered constant headache and Moyamoya syndrome was dignosed. She had an encephaloduroarteriosynangiosis when she was 10yrs 4month old. Case 3 suffered from spontaneous bacterial peritonitis and recurrent rhabdomyolysis along with neutropenia and thrombocytopenia before KT. In three years of KT his neutropenia and thrombocytopenia aggravated and bone marrow study suggested aplastic anemia. Hematopoietic stem cell transplantation is under consideration.
In summary, SIOD is a rare systemic disease presenting as FSGS. While KT is indicated for their ESRD, their extra-renal symptoms progress regardless of KT. With its defective cellular immunity multiple infections complicate the clinical course after KT in SIOD.