The pathogenesis of systemic lupus erythematosus (SLE) has been attributed to complex interactions between genetic, hormonal and environmental factors. The influence of a genetic predisposition to SLE is supported by family aggregation and a high concordance rate in monozygotic twins. Here we present a rare case of simultaneous presentation of SLE and lupus nephritis in a mother and son. Both patients had nephrotic-range proteinuria, and the renal pathological classifications of the son and his mother were Class IV-G (A) and Class III (A/C), respectively, according to the International Society of Nephrology/Renal Pathology Society (ISN/RPS) 2003 classification of lupus nephritis. Apart from the renal involvement, both patients had leucopenia and anemia, and the mother also had typical cutaneous lesions and secondary Sjögren’s syndrome. This case supports the genetic role in the etiology of SLE, and displayed different clinical presentations and disease severity in familial SLE patients of different gender and age.