May-Hegglin Anomaly-Associated Nephropathy: A Case Series

Introduction: May-Hegglin Anomaly (MHA) is a rare autosomal dominant disease associated with a mutation in MYH-9 gene and it is characterized by macrothrombocytopenia, large platelets and neutrophils with abnormal cytoplasmic inclusions. Clinical features of this disease include hearing loss, early cataracts, and renal failure. The MYH-9 gene is associated with MYH-9 Related Disorders (MYH9-RD), such as Fecthner (FTNS) and Sebastian (SBS) syndromes. Case Description: We present two interesting cases of renal injury attributed to May-Hegglin Anomaly. The first is a 52-year-old Hispanic female with May-Hegglin Anomaly (MHA) associated with nephropathy and thrombocytopenia complicated by stage 3 chronic kidney disease (CKD) and hypothyroidism. She was found to have a pathogenic MYH-9 heterozygous mutation and she met the clinical criteria for May-Hegglin Anomaly. The patient is not a candidate for kidney biopsy due to low platelets secondary to her May-Hegglin Anomaly. She has been treated with SGLT-2 inhibitors, ARBs for managing her CKD and Synthroid® for hypothyroidism. She continues to have low platelets, proteinuria, and her CKD continues to progress. Our second case highlights a 39-year-old white female with MHA associated with focal segmental glomerulosclerosis, diagnosed at the age of 15 on renal biopsy, thrombocytopenia, and mix connective tissue disorder with rheumatoid arthritis and systemic lupus erythematosus clinical features. She is currently on a treatment regimen of methotrexate, Xeljanz, and IVIG for her rheumatological diseases. Her kidney function has remained stable on ACE inhibitors, HCTZ and as needed loop diuretics for her frequent edema. Discussion: These cases illustrate the challenges with diagnosing and managing the renal complications associated with MHA due to the MYH-9 gene mutation. The chronic thrombocytopenia in both patients restricts the use of invasive diagnostic procedures such as biopsies that is critical for confirming relation between nephropathy and MHA. This further limit the possibility for more targeted treatment. Thus, these cases stress the importance of genetic testing as a factor in diagnosing and stress the challenge of managing patients with suspected MHA with associated nephropathy and thrombocytopenia. Further studies are needed to improve and understand the management of this rare condition.