Autosomal Dominant Polycystic Kidney Disease (ADPKD) (Malattia policistica autosomica dominante o dell’adulto) The most common of inherited cystic disease It occurs worldwide and in all race Prevalence 1:400 – 1:1000 Male/Female 1.2 – 1.3 More progressive in men than in women Genetics of ADPKD La malattia è dovuta a mutazioni di almeno 2 geni PKD1 – braccio corto del cromosoma 16 (16p13.3) – 85% circa dei casi sintomatici PKD2 – braccio lungo del cromosoma 4 (4q21) (lungo=q, corto=p) Genetics of ADPKD PKD1 encode polycystin -1 (PC1) PKD2 encode polycystin -2 (PC2) PC1 and PC2 constitute a subfamily of proteins of Transient Receptor Potential channels (TRP) PC2 (or TRPP2) exhibit structural and functional characteristics of TRP channel. 6 transmembrane domains. PC1 (TRPP1) is a distant TRP homolog in final COOH region. 11 transmembrane domains. Protein Produts of PKD genes Polycystin-1 Broad tissue expression: (immunolocalization) – Kidney (lateral membrane of tubular cells) – Brain – Heart – Bone – Muscle Polycystin-2 Broad tissue expression: (immunolocalization) – Kidney (all nephron segments) – Heart – Ovary – Testis – Vascular smooth muscle – Small intestine PKD1 IS MORE SEVERE THAN PKD2 ASSOCIATED DISEASE Age at ESRD: PKD1 54.3 years PKD2 74 years Development of cysts: PKD1 more cysts at an early age Not to faster cyst growth PKD1 and 2 can be associated with severe polycistic liver disease Prevalence of PKD2 associated disease (10-15 %) has likely been underestimated in clinical study In population-based study PKD2 reveal higher relative frequencies (36-29 %) PKD1 and PKD2 mutations are highly variable and usually private Autosomal Dominant Polycystic Kidney Disease: Mutation Database – PKD foundation (16-3-2015) PKD1 mutations: – 2322 mutazioni elencate nel database, classificate come certamente patogenetiche, patogenetiche con elevata probabilità, probabilmente patogenetiche, indeterminate e probabilmente non patogenetiche PKD2 mutations: – 278 mutazioni elencate nel database – http://pkdb.mayo.edu/ ADPKD mutazioni a carico del gene PKD1 mutazioni a carico del gene PKD2 proteine tronche e quindi inattive, specifiche per ciascuna mutazione (e quindi per ciascuna famiglia). proteine tronche e quindi inattive, specifiche per ciascuna mutazione (e quindi per ciascuna famiglia). PATOGENESI inversione della polarità DIAGNOSI 1)Paziente con malattia conclamata (reni di grandi dimensioni, policistici, ipertensione, riduzione della funzione renale) 2)Diagnosi precoce nel paziente a rischio 3)Diagnosi prenatale/preimpianto Renal ultrasound Commonly used because of cost and safety. Revised ultrasound criteria improve the diagnostic performance The presence of at least 3 (unilateral or bilateral) renal cysts in at-risk individuals aged 15–39 years 2 cysts in each kidney in at-risk 40–59 years 4 or more cysts in each kidney for at-risk individuals aged 60 years 3 or more cysts (unilateral or bilateral) has a positive predictive value of 100% in the younger age group and minimizes false-positive diagnoses 2.1 and 0.7% of the genetically unaffected individuals younger than 30 years have one and two renal cysts, respectively. In the 30–39 years old, both the original (2 cysts in each kidney) and the revised (>3 cysts, unilateral or bilateral) criteria have a positive predictive value of 100%. Genetic testing Limitations either by linkage or mutation analysis. Linkage analysis requires accurate diagnosis, availability and willingness of sufficient affected family members to be tested and is feasible in fewer than 50% of families. De novo mutation can also complicate interpretation of results. Molecular testing by direct DNA sequencing is now possible with likely mutations identified in 90% of patients. However, as most mutations are unique and up to onethird of PKD1 changes are missense, the pathogenicity of some changes is difficult to prove. Clinica Liver Others Kidneys ADPKD Cerebral arteries Intestines Heart Enlargement of renal cysts and chronic renal failure. Total kidney volume and cyst volumes increased exponentially. Mean increase over 3 years was 5.27% per year. The rates of change of total kidney and total cyst volumes, and of the right and left kidney volumes, were strongly correlated. Baseline total kidney volume predicted the subsequent rate of increase in renal volume. GFR declines in patients with baseline total kidney volume above 1500 ml. CRISP Study: 241 pts. ; eGFR 60 ml/min; followed prospectively with yearly MR examinations. Confirmed by European study Renal manifestations 1 Hypertension 60-100% 2 Kidney failure 50% by age 50 3 Gross ematuria 50 % 4 Infection common 5 Kidney stones 20-25 % Ipertensione Precoce (5% bambini, 40% giovani con funzione renale norma, 89% ESRD) Severa (rapida insorgenza di LVH) Sodio-sensibile - non dipper Aumenta l’incidenza di complicanze cardiovascolari Aumenta il rischio di emorragia subaracnoidea Trattamento (in mancanza di studi controllati): Target pressorio < 125/75 mmHg Farmaco di prima scelta: un ACE-inibitore o un sartanico (finché non controindicato per l’iperkaliemia) Praticamente sempre necessaria una terapia di associazione (spesso 3 o più farmaci) e l’uso di ipotensivi potenti _____________________________ Cyst complications _________________________________ 1 Hypertension 2 Kidney failure 3 Gross ematuria 4 Infection 5 Kidney stones Renal cyst rupture Clinical presentation: 1. Acute colicky pain 2. Gross hematuria (Approximately 42% to greater than 50% of ADPKD patients) A. self-limited, B. lasting for 2–7 day Causative factors for gross hematuria: 1. UTI (most frequent especially among women ) 2. Sports 3. abdominal surgeries 4. kidney stones 5. cyst ruptures Earlier onset of bleeding (ie, younger than 30 years), and more frequent episodes may indicate a risk of worsening renal function (Johnson and Gabow 1997) . The incidence of gross hematuria is related to both kidney size and hypertension (Gabow et al 1992). Treatment Bed rest Hydration Analgesic administration NSAIDs should be limited Nephrectomy or renal arterial embolization (hematuria so serious and persistent) Infected renal cysts Symptoms: • Fever • Flank pain (not radiate and is not relieved by positioning) Laboratory findings: • Urinalysis and cultures may be negative with cyst infection • Blood cultures are positive in most of the cases Imaging methods for diagnosis: Contrast enhanced CT MRI Scintigraphy with 111-indium labeled leukocytes Treatment Lipophilic agents such as : 1. 2. 3. 4. 5. 6. Clindamycin Ciprofloxacin Norfloxacin Trimethoprim- sulfamethoxazole Therapy should continued for 6 weeks Cyst drainage in resistant cases Kidney stones The prevalence in ADPKD adult patients ranges from 20% to 36% 20 to 28% of these patients are symptomatic Presentations of nephrolithiasis in ADPKD: 1. Flank pain 2. Hematuria 3. UTI The most common renal stones in ADPKD are uric acid stones (50%), which is a much higher incidence compared to the general population Pathophysiology: 1. Metabolic defects (Hypocitraturia occurring in approximately 60% and 49% of ADPKD patients with and without stones respectively). 2. Urinary stasis within structural abnormalities due to cyst compression (more stone-forming, higher cyst numbers). Kidney failure In most patients, renal function is maintained within the normal range, despite relentless growth of cysts, until the fourth to sixth decade of life. By the time renal function starts declining, the kidneys usually are markedly enlarged and distorted with little recognizable parenchyma on imaging studies. At this stage, the average rate of GFR decline is 4.4– 5.9 ml/min/year. Fattori determinano più rapidamente la perdita della funzione renale Immodificabili: Sesso maschile, enia afro-americana Modificabili: Ipertensione, ematuria, infezioni delle vie urinarie (forse nell’uomo), gravidanze (?) ADPKD - Chronic pain Cyst formation and progressive kidney enlargement may cause a dull, chronic pain. The source of mechanical back pain: Larger renal volumes (traction of the renal capsule) hypertrophic lumbosacral muscle groups ADPKD Acute abdominal pain CAUSE FREQUENCY Kidney Cyst Bleending ++++ Stone ++ Infection + Infection rare Liver Cyst Bleending very rare Cerebral aneurysms Hepatic and pancreatic cysts Malformations of selected vasculature, Cystis in other organs Extraren Complicanze al complicat extrarenali ions Abdominal wall and inguinal hernia Cardiac valve disease Colonic diverticula diverticulitis Hepatic cysts Prevalence Female : range from 58%–75% Male: from 42 to 62%. Hepatic cyst volume is larger in women than in men. Despite the progressive nature of the cystic disease, the hepatic parenchyma retains its normal pattern and function Complicanze Tutte estremamente rare ad eccezione delle delle cisti asintomatiche (80 – 90% dei casi) e del reflusso gastroesofageo Polycystic liver disease Associated with both PKD1 and non-PKD1 genotypes. Also occurs as a genetically distinct disease in the absence of renal cysts. Similar to ADPKD, ADPLD is genetically heterogeneous, with two genes identified (PRKCSH and SEC63) accounting for approximately one-third of isolated ADPLD cases. Cystis in other organs Seminal vesicles 40–60% (males) – Sperm abnormalities and defective motility (asthenozoospermia or <50% of spermatozoa with forward motility) are common in ADPKD and rarely may be a cause of male infertility Pancreas 5 % Arachnoid 8% of patients Epididymal and prostate cysts may also occur with increased frequency Intracranial aneurysms In the general population the estimated prevalence of ICAs derived from autopsy studies is 1%–5%. In contrast ICAs are seen in approximately 4%– 11.7% of ADPKD patients. The risk of subarachnoid hemorrhage (SAH) is approximately fivefold higher in ADPKD patients. In the general population, the incidence of SAH resulting from a ruptured ICA is about 0.05% per year Aneurysmal bleeding in ADPKD patients tends to occur at a younger age with a mean age of 35–45 years. RICAs are responsible for approximately 80% of SAH’s. The mortality rate within 30 days after bleeding is almost 45%. About 25% of ADPKD patients with a previous ICA developed a new ICA over a mean period of 11.4 years Il rischio di aneurismi cerebrali e della loro rottura dipende da particolari mutazioni ed ha quindi base familiare. Screening (angio-RM): a) Nei pazienti con storia familiare b) Nella valutazione pretrapianto Other vascular manifestations Thrombosis of arterovenous fistula (?) Thoracic aortic and cervicocephalic artery dissections Coronary artery aneurysms. Valvular heart disease – mitral valve prolapse (26%) – aortic insufficiency occurs with increased frequency – Other valves. They are caused by alterations in the vasculature directly linked to mutations in PKD1 or PKD2. Other manifestations Colonic diverticulosis and diverticulitis are more common in ESRD patients with ADPKD than in those with other renal diseases. Extracolonic diverticular disease. A rarely reported association of ADPKD is with idiopathic hypertrophic pyloric stenosis Bronchiectasis are detected by CT three times more frequently in ADPKD compared with control individuals (37 vs 13%, P<0.002). TREATMENT Blood pressure Renal failure Chronic pain Novel Therapy NOVEL THERAPIES Attivi sulla proliferazione dell’epitelio cistico inibitori di mTOR (sirolimus, everolimus) Attivi sul trasporto di acqua dall’interstizio al lume delle cisti AMPc dipendente inibitori del recettore V2 dell’ADH (vaptani) somatostatina ed analoghi (octreotide)