Abstract: FR-PO0063
A Stroke of Bad Cysts: A Case of Renal Cysts and Intracerebral Hemorrhage
Session Information
- ADPKD and Cystic Kidney Disease - 2
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Cystic (Monogenic)
Authors
- Seethapathy, Ritu, Mass General Brigham Inc, Boston, Massachusetts, United States
- Klufas, Andrew, Roger Williams Medical Center, Providence, Rhode Island, United States
- Lundquist, Andrew L., Mass General Brigham Inc, Boston, Massachusetts, United States
Introduction
Hereditary Angiopathy, Nephropathy, Aneurysms, and Muscle Cramps (HANAC) syndrome is a rare autosomal dominant disorder caused by mutations in the COL4A1 gene. This gene encodes the α1 chain of type IV collagen,a primary component of vascular and epithelial basement membranes. While the syndrome is often identified by CNS findings,renal manifestations such as bilateral renal cysts and hematuria can lead to clinical misdiagnosis as Autosomal Dominant Polycystic Kidney Disease (ADPKD).
Case Description
A 41-year-old male with a history of hypertension was referred for evaluation of incidentally discovered renal cysts and a family history of cystic kidney disease.His father was reportedly monitored for bilateral cysts and hematuria but had not progressed to kidney failure. Initial assessment revealed normal GFR and trace hematuria.Three years after initial presentation, the patient suffered a right basal ganglia intraparenchymal hemorrhage.Notably, his systolic blood pressure at the time of the event was only moderately elevated(130–150 mmHg).Given the combination of early-onset stroke and atypical renal cysts, genetic testing was pursued, which identified a deletion in the COL4A1 gene,confirming a diagnosis of HANAC syndrome.
Discussion
Identifying HANAC syndrome is critical for specific preventive stategies & management in patients who may otherwise be classified under the umbrella of ADPKD or Alport syndrome.Primary management focuses on aggressive blood pressure control and surveillance for aneurysms and ocular complications.Anticoagulants and antiplatelets must be avoided due to intrinsic vessel fragility.Timely diagnosis is helpful in genetic counseling and proactive screening of asymptomatic relatives who may be at risk for "silent" brain aneurysms.This case highlights the essential role of genetic testing in atypical cystic kidney disease and the importance of recognizing the systemic implications of type IV collagen defects