Alport syndrome, also known as hereditary nephritis, is a rare inherited congenital disease that most often involves progressive sensorineural hearing loss during school age and affects renal, visual and auditory systems. It is caused by a defect in the synthesis of collagen, a protein that constitutes the fundamental structure of connective tissue and is essential for the basement membranes of the kidneys, eyes and ears.
The alteration of collagen synthesis causes progressive renal fibrosis with consequent chronic renal failure, known as progressive hereditary heterogeneous nephropathy and characterized by presence of blood in the urine (hematuria) and loss of proteins (proteinuria). Fibrosis also affects the ear, with greater frequency in men, causing progressive deafness. In terms of eyesight, retinal lesions and intraocular hypertension with visual impairment may occur. In 1996 Gregory et Al. provided 10 criteria needed to diagnose Alport Syndrome, at least four of which must be found:
Genetically, Alport syndrome is predominantly linked to the X chromosome. The Alport syndrome was described in 1927 by Dr. Artur Cecil Alport who identified the presence of numerous cases of hematuria (blood in the urine) and deafness in different members of the same family. In this family, males had a very severe renal disease associated with hearing loss symptoms, while females had some degree of hearing loss and hematuria, without renal impairment. The disease varies from individual to individual, even within the same family, involving both children and adults. It is unpredictable both in terms of when it can manifest itself and for the progression and the different involvement of the various organs.
Hearing damage is represented by a bilateral and progressive sensorineural deafness that requires the use of hearing aids. Hearing loss generally begins by affecting the high frequencies and then progresses to the medium and low frequencies. The evolution of deafness, which cannot be assessed in advance in terms of time and severity, determines a reduction in verbal comprehension, especially in noisy environments which, associated with visual deficiencies (lenticonus or retinopathy), alters normal social relationships and work potential, resulting in communication problems or isolation and depression. The application of customized hearing aids is fundamental to limit and block these consequences. However, considering that this syndrome can cause deafness, the risk of damage to the eye is lower compared to the one concerning the ear.
At the moment, there is no specific therapy for Alport syndrome: usually a blood and urine test, ENT audiometric examination and periodic eye check ups are used. The approach is mainly preventive: establishing pharmacological or dietary therapeutic regimens to try to slow down the progression towards end-stage renal failure. Primary prevention consists of preventing the transmission of the disease with a correct preconceptional and prenatal genetic and diagnostic approach. Secondary prevention consists of periodic check-ups with blood and urine tests, ENT check ups, audiometric and ophthalmological examinations.
In children, it is of fundamental importance to carry out appropriate therapy to slow the course of chronic renal failure. Conservative treatment is aimed at proper nutrition with a low-protein diet, which can help delay the start of dialysis (low in protein and mineral salts). In extreme cases, Alport syndrome determines one of the most serious forms of nephritis - responsible for 1-2% of renal failure cases throughout Europe - forcing the patient to face a long clinical dialysis treatment and subsequently a transplant.