Mutations in the αB-crystallin gene (CRYAB) have been reported in desmin-related myopathies, with or without cardiac involvement. Mutations in this gene have also been documented in large multi-generation families with autosomal dominant congenital posterior pole cataract (CPPC). In these congenital cataract families no cardiac or muscular phenotype was reported. This report describes a family with an unusual read-through mutation in CRYAB, leading to the elongation of the normal αB-crystallin protein with 19 amino acid residues. Affected family members combine a CPPC with an adult onset dilated cardiomyopathy (DCM), thereby expanding the αB-crystallinopathy phenotype. Repolarisation abnormalities preceded the onset of cardiomyopathy and were already present in childhood. No skeletal myopathy was observed. This report illustrates that congenital cataract can be a prelude to more severe disease even outside the context of inborn errors of metabolism. The identification of a CRYAB mutation in this family supports the notion that mutations in this gene are a rare cause of genetically determined DCM. The combined congenital cataract/cardiomyopathy phenotype adds to our understanding of the complex phenotypic spectrum of αB-crystallinopathies.

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Background and Aims Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disease and is characterized by genetic complexity and phenotypic variability. The age of reaching kidney failure (KF) is variable and covers the complete age-spectrum. There is an unmet need for early biomarkers to differentiate between rapid and slow progressors. The PROPKD score identified hypertension before the age of 35 years as a risk factor for rapid kidney function decline. We aim to identify earlier risk factors for rapid disease progression by studying a population of ADPKD patients who reached kidney failure (KF) before the age of 40y. Method This multicentric retrospective study focusses on a unique population (n = 200) of ADPKD patients who reached KF before 40y. Kidney failure (KF) was defined as CKD5 or start of Kidney Replacement Therapy (KRT), whichever came first. Longitudinal data on childhood history, comorbidities and kidney function were collected. Life table and Proportional Hazards analysis were used to assess associations between clinical parameters and time to KF. Results Median age of ADPKD diagnosis was 22.3 (16.5 – 28.6) and median age of KF onset was 36.2 years (32.9-38.7 years). Fourty-seven patients were genotyped (23.5%) of which 38 patients (81.0%) were PKD1T and 8 (17.0%) were PKD1NTand only 1 patient (2.1%) was PKD2. Median age at first urological event was 27.0 (20.7 – 32.0) years. 71 patients (35.5%) had history of UTI's, 67 patients (33.5%) had hemorrhagic cysts on abdominal imaging, 66 patients (33.0%) presented with gross hematuria and 40 patients (25.0%) presented with kidney stones. There was a high prevalence of hypertension (N = 128, 64.0%). Four patients (N = 4/128, 3.1%) had a very early diagnosis of hypertension before the age of 10 years. Hypertension-onset before the age of 18 years correlated with a significantly faster progression (UV HR: 2.07 (1.32 – 3.25)). Conclusion This study describes a unique cohort of ADPKD patients with rapid disease progression. Hypertension at young age (<18) correlated with rapid disease progression, suggesting that ambulatory blood pressure in children might be useful to identify patients at risk for rapidly progressive ADPKD.

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