Nephropathies by anomaly of collagen IV

The nephropathies by anomaly of collagen IV include/understand a whole of clinical demonstrations which go from the syndrome of Alport to simple a hématurie manifestation of nephropathy to fine basal membrane. It corresponds to a hereditary anomaly of the basal membranes of the clusters of the kidney, eye and ear.

The syndrome of Alport (described in 1927 by Dr. Cecil A. Alport among members of a British family) associates renal, ocular and auditive anomalies.

The syndrome of Alport has, in 80% of the cases a transmission related to the X chromosome, in 15% of the cases a recessive transmission and 5% of the cases a dominant transmission.

The principal demonstration of the syndrome of Alport is the microscopic Hématurie which starts early in childhood in the form related to X as much among women that at the men. The men having the form related to X develop a protéinurie almost systematically then an impaired renal function appears leading to the kidney machine in 60% of the cases before 30 years and 90% of the cases before 40 years. The women reached by this form develop a final Impaired renal function in 30% of the cases before 60 years.

The auditive demonstrations start at the beginning of adolescence. Among women the demonstrations are later and seldom lead to a deafness.

In the recessive form the hématurie reaches the man as much as the woman and the dyalise is frequently necessary before 30 years. The hearing impairment starts early in this form. However, this form is spread little, the statistical figures miss.

The dominant form appears much more tardily. The hearing impairment starts rather late in this form.

The ocular lesions appear especially in the forms related to X chromosome and recessive. They consist of yellowish tasks around mackled.

The nephropathy with fine basal membrane is of dominant transmission and is limited mainly to renal demonstrations and seldom require the kidney machine.

Other names

Etiology

Incidence & prevalence

Description

Diagnosis

A renal biopsy makes it possible to check the renal attack. A cutaneous biopsy makes it possible to check the mode of transmission by seeking the anomaly related to X of collogene. This cutaneous biopsy does not make it possible to pose a diagnosis.

Treatment & assumption of responsibility

No treatment to date exists. Regularly, of the attempts exist for stage with the important protein losses which damage the basal wall. Immunosuppresseurs showed signs of success on a study in Barcelona (Spain) but they cause the risk of impaired renal function. They were based on the reduction of the hématurie always important at nephropathies. Immunotenseurs are currently tested in several hospitals, the side effects are there too very important. A désodé mode, a regular contribution out of calcium and vitamin (to fight against the nephrotic syndrome pure), and of the regular analyzes seem to be to date only the methods of action in rem. Specialized consultations (Necker Hospital for the Syndrome of Alport) exist.

The genetic Council

Sources

Clifford E Kashtan, Collagen IV-Related Nephropathies (Alport Syndrome and Thin Meanly Nephropathy Membrane) In: GeneReviews At GeneTests: Medical Genetics Information Resource (database online). Copyright, University off Washington, Seattle. 1997-2005.

Associations

AIRG : association information and research genetic renal diseases

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