PKD1 Compared With PK D2 Genotype and Cardiac Hospitalizations in the Halt Progression of Polycystic Kidney Disease Studies

Hypertension increases PPV for polycystic kidney disease in PKD1 and PKD2 variant carriers

Autosomal dominant polycystic kidney disease (ADPKD) is the leading genetic form of KD. Although rare causal variants in the PKD1 and PKD2 genes have been identified, their penetrance and the disease progression and outcome are known to vary, and treatment efficacy in these carriers lags compared to patients with other forms of chronic KD (CKD). To develop a population screening strategy with high sensitivity to individuals likely to develop disease, we characterize the presentation and progression of ADPKD in variant carriers, identified in a multi-center all-comers cohort, as well as the UK Biobank. We show that the positive predictive value of hypertension for future diagnosis of KD is extremely high: 74% and 66% for PKD1 and PKD2, respectively. It is also highly preemptive, with hypertension occurring an average of 11 years before a KD diagnosis. Using pre-disease time point measurements of kidney function prior to their ADPKD diagnosis, we find that PKD1 and PKD2 variant carriers show significantly decreased kidney function (EGFR) an average of 5 years before their clinical diagnosis. Unlike other CKD patients, 54% of variant carriers with hypertension meet the diagnostic threshold for CKD years prior to their disease diagnosis, and their EGFRs are statistically indistinguishable from variant carriers who have already been diagnosed. These findings suggest that a population screening strategy using a combination of targeted sequencing and routine monitoring could identify cases of ADPKD with high sensitivity and support initiating treatment years prior to the current standard of care.

Glioneuronal tumor in an autosomal-dominant polycystic kidney disease patient: a case report and literature review

Introduction

The association between primary brain tumors, such as glioneuronal tumors, with autosomal-dominant polycystic kidney disease (ADPKD) remains poorly understood, with only two cases reported excluding this one. This case of an ADPKD patient diagnosed with a rosette-forming glioneuronal tumor highlights an exceptionally rare potential association warranting further investigation.

Case presentation

A 28-year-old male with ADPKD presented with progressive ataxia, dizziness, and headache. MRI revealed a cerebellar mass and obstructive hydrocephalus. Surgical resection and histopathological examination confirmed the diagnosis of a rosette-forming glioneuronal tumor. Postoperatively, the patient showed significant symptom improvement.

Discussion

The interplay between genetics and glioneuronal development is complex and underexplored. While most glioneuronal arise sporadically, rare genetic syndromes may predispose individuals to these tumors. Additionally, although more than 70 cases of ADPKD with concurrent tumors were reported, the literature on this specific association remains limited.

Conclusion

This case underscores the need for heightened awareness of potential associations between ADPKD and tumors such as glioneuronal tumors. With limited literature on this subject, further research is imperative to understand the underlying mechanisms and clinical implications. Enhancing our knowledge in this area can improve patient outcomes and management strategies.

The Pathophysiology of Left Ventricular Hypertrophy, beyond Hypertension, in Autosomal Dominant Polycystic Kidney Disease

Heart disease is one of the leading causes of death in autosomal dominant polycystic kidney disease (ADPKD) patients. Left ventricular hypertrophy (LVH) is an early and severe complication in ADPKD patients. Two decades ago, the prevalence of LVH on echocardiography in hypertensive ADPKD patients was shown to be as high as 46%. Recent studies using cardiac magnetic resonance imaging have shown that the prevalence of LVH in ADPKD patients may be lower. The true prevalence of LVH in ADPKD patients is controversial. There is evidence that factors other than hypertension contribute to LVH in ADPKD patients. Studies have shown that young normotensive ADPKD adults and children have a higher left ventricular mass index compared to controls and that the prevalence of LVH is high in patients with ADPKD whose blood pressure is well controlled. Polycystin-1 (PC-1) and polycystin-2 (PC-2) control intracellular signaling pathways that can influence cardiac function. Perturbations of PC-1 or PC-2 in the heart can lead to profound changes in cardiac structure and function independently of kidney function or blood pressure. PC-1 can influence mammalian target of rapamycin and mitophagy and PC-2 can influence autophagy, processes that play a role in LVH. Polymorphisms in the angiotensin-converting enzyme gene may play a role in LVH in ADPKD. This review will detail the pathophysiology of LVH, beyond hypertension, in ADPKD.