Monogenic Lupus with IgA Nephropathy Caused by Spondyloenchondrodysplasia with Immune Dysregulation

Abstract

Monogenic disorders causing systemic lupus erythematosus represent a small subset of cases. Type-1 interferonopathies, like spondyloenchondrodysplasia with immune dysregulation constitute an important functional category of monogenic lupus. Apart from autoimmune disorders, neurological and skeletal abnormalities are additional manifestations observed in this disorder. A young female presented with seizures due to acute hemorrhagic stroke secondary to malignant hypertension. On evaluating the cause for hypertension, there was evidence of glomerulonephritis and multiple autoantibodies positivity including dsDNA. A diagnosis of lupus was made based on clinical and laboratory findings. Kidney biopsy revealed mesangial proliferative glomerulonephritis with predominant IgA deposits favouring IgA nephropathy. Additional features in the form of short stature with vertebral abnormalities and bilateral basal ganglia calcification led to evaluation of Type-1 interferonopathies. Sanger sequencing identified a novel compound heterozygous variants c.550C<T (p.Q184*) in exon 3 and c.740T<G (p.L247R) in exon 4 of ACP5 gene. Parents were found to be carriers of the variants in ACP5 gene. Management included antihypertensive agents and symptomatic therapy. On follow-up, there was complete resolution of glomerulonephritis and normalization of blood pressure. This case report documents the classic phenotype comprising autoimmune, skeletal, and neurological abnormalities in spondyloenchondrodysplasia with immune dysregulation with a novel variant on Sanger sequencing in an Indian patient. This report also highlights the rare coexistence of IgA nephropathy in monogenic lupus.