Prevalence and risk factors for dilatation of sinus of Valsalva in boys with X-linked Alport syndrome

Abstract

X-linked Alport syndrome is multisystem disease caused by mutation in COL4A5. Aortic dilatation described in X-linked Alport syndrome is considered a specific manifestation of the disease.Purpose. To define prevalence and risk factors for aortic dilatation in boys with X-linked Alport syndrome.Methods. Retrospective cross-section single center study included boys with X-linked Alport syndrome (n=67, age 10.2±4.6), comparison group consisted of boys with congenital urinary tract abnormalities (n=20, age12.2±4.8). All patients underwent on clinical-laboratory examination and echocardiography. Aorta was measured in the parasternal long-axis view at level of the sinus of Valsalva, aortic dilatation was determined by z-score >2 for BSA.Results. The prevalence of sinus of Valsalva dilatation did not differ between two groups (0.1 vs 0.15; p=0.47). The sinus of Valsalva dilatation was associated with body mass index (p=0.019), left ventricular diastolic diameter (p=0.01) and left ventricular mass (p=0.01) in children with congenital urinary tract abnormalities, with body mass index (p=0.02) and left ventricular diastolic diameter (p=0.03) in boys with Alport syndrome. No statistically significant effect of blood pressure level, proteinuria, eGFR and type of COL4A5 mutation on aortic dilatation has been demonstrated.Conclusion. The prevalence of aortic dilatation in boys with X-linked Alport syndrome is higher than in general population, but comparable to children with congenital urinary tract abnormalities. The body mass index and left ventricular diastolic diameter were associated with aortic dilatation in Alport syndrome males. We did not show the relationship between blood pressure load, proteinuria, eGFR and aortic dilatation. Study limitations: small sample size, prevalence of young patients with chronic kidney diseases stage 1–2 and missense mutations in the COL4A5 gene.