■Fu Wenning
Xiaohao suffered from chronic nephritis when he was 4 years old. After more than ten years of treatment, the effect was always unsatisfactory. After several inquiries, he came to the outpatient clinic of Director Lu Ying of the Department of Nephrology and Rheumatology of Zhejiang Litongde Hospital. After detailed consultation, he was diagnosed with a rare kidney disease – Alport syndrome. This is a hereditary kidney disease, which is rooted in parents .
Alport syndrome is one of the 121 rare diseases in the first batch of rare diseases in my country published by China in 2018, and it is also the most common inherited kidney disease. Autosomal dominant Alport syndrome accounts for about 1/100 of the population, while severe X-linked inheritance accounts for about 1/2000.
Alport syndrome can begin in early childhood. Typical clinical manifestations include renal, ocular changes, and hearing impairment. Renal manifestations are hematuria, proteinuria, and progressive deterioration of renal function. Among them, hematuria is often persistent microscopic hematuria. Gross hematuria may occur after exercise or during fever, and is more common in juvenile type.
The hearing changes to sensorineural hearing loss, which gradually worsens with the course of the disease, but it should be noted that patients with X chromosome-linked inheritance who progress to ESRD may not necessarily have obvious hearing loss, so hearing loss cannot be regarded as a The inherent characteristics of Alport syndrome, otherwise it is easy to cause missed diagnosis. Ocular abnormalities manifested as myopia, youth rings, and cataracts, but lacked specificity.
Three ocular changes of diagnostic significance include: anterior conus lens, posterior polymorphic corneal atrophy, and retinal macules (white or yellow granules around the foveal area of the retina). The incidence of hearing impairment in male patients in my country is higher than that reported in foreign countries (68% vs. 55%), and that in women is lower than that reported in foreign countries (7% vs. 45%). The incidence of ocular abnormalities is similar to that reported in foreign countries. Leiomyomas can also occur in a small number of patients, which can involve the respiratory tract, gastrointestinal tract, and female reproductive tract; aneurysmal lesions, midface dysplasia, and mental retardation have occasionally been reported.
Patients often have a family history. Patients with autosomal recessive inheritance or male patients with X-linked inheritance have a faster disease progression and often enter end-stage renal disease at the age of 16 to 35 years; while female patients with autosomal dominant inheritance and X-linked inheritance often have a slower course of disease and renal failure. Appears late.
Early diagnosis of Alport syndrome is very important. When the following conditions occur, the possibility of Alport syndrome should be highly vigilant: juvenile or juvenile onset, chronic nephritic syndrome or early chronic renal insufficiency; family history of similar diseases ; Accompanied by high-frequency hearing loss, characteristic ocular lesions (anterior conical lens or retraction or retinal macules).
At this time, renal biopsy pathology is crucial for diagnosis, such as extensive GBM thickening, thinning, and characteristic changes of delamination, and type IV collagen immunostaining in kidney or skin tissue The absence or abnormal distribution of α4 chain and (or) α5 chain is highly suggestive of this disease. Skin biopsy may be performed if renal biopsy is contraindicated. Diagnosis requires testing for COL4A3, COL4A4, or COL4A5 gene defects. Genetic testing can determine the inheritance pattern, and sometimes help to distinguish between early-onset renal failure and extrarenal manifestations, and help guide patients with prenatal and postnatal care, which is of great significance.