Familial hemorrhagic nephritis

　　What are the causes of the onset of familial hemorrhagic nephritis?

　　Familial hemorrhagic nephritis, also known as Alport syndrome, is a monogenic genetic disease, and the patients are heterozygotes. It is believed that the genetic heterogeneity of the disease exists, with a total of 3 modes of inheritance, namely X-linked dominant inheritance, autosomal dominant inheritance, and autosomal recessive inheritance.1. X-linked dominant inheritance:

　　This is the main genetic mode of the disease. Since the causative gene is located on the X chromosome, inheritance is related to gender. The disease can be passed from the mother to both sons and daughters, and the risk of disease in offspring is equal, 50%. The disease is not passed from the father to the son, but to all daughters. Therefore, there are more female patients than male patients in the family, but the disease is more severe in males, because females have one normal homologous chromosome (heterozygote), while males do not (hemizygote).2. Autosomal dominant inheritance:

　　1/7 to 1/3 of pedigrees inherit this way. Since the causative gene is located on an autosomal chromosome, inheritance is unrelated to gender. Children of affected parents have an equal chance of getting the disease, about half, regardless of whether they are male or female, and the disease can be passed from the father to the son. The severity of the disease is unrelated to gender, and the severity of the disease is similar for males and females.3. Autosomal recessive inheritance:

　　Familial hemorrhagic nephritis can easily lead to what complications

　　The main clinical symptoms of familial hemorrhagic nephritis include renal manifestations, hearing loss, and ocular defects. The specific symptoms are as follows:

　　1. Renal manifestations
　　1. The most prominent clinical manifestation is hematuria. Affected male patients show persistent microscopic hematuria, and many patients experience sudden onset of gross hematuria after upper respiratory tract infections before the age of 20; affected females are often heterozygotes and may exhibit intermittent hematuria, with 10% to 15% of heterozygous female carriers never experiencing hematuria; affected boys can develop hematuria within the first year of life, and it is likely to occur at birth.
　　2, Male patients with this disease often eventually develop proteinuria, which starts as trace proteinuria and increases with age, often developing into nephrotic syndrome. The incidence and severity of hypertension also increase with age. Although the syndrome can develop into renal failure before the age of 10, most patients develop end-stage renal disease between the ages of 20 to 50. Male patients have a poor prognosis, and all male patients will develop end-stage renal disease, with significant interfamily variation in the rate of progression.

　　Two, Hearing Loss
　　The hearing loss in patients is not congenital but often occurs around the age of 15 in male patients. In the members of the affected family, hearing damage often accompanies renal damage. In the early stage, hearing loss can only be detected by hearing tests, with bilateral hearing loss reduced to the range of 2000 to 8000 Hz. The hearing loss in male patients is progressive and will eventually affect other frequencies, including the frequency of voice; in female patients, hearing loss is less frequent and tends to occur at a later age. Progressive hearing loss in female patients predicts an adverse renal disease outcome.

　　Three, Ocular Defects
　　1, Ocular defects, although not as common as deafness, are also very common, with an incidence rate of 15% to 30%. The anterior lenticonus (i.e., the central part of the lens forming a conical protuberance in front of the anterior capsule) is essentially the characteristic lesion of the disease. The anterior lenticonus is generally not present at birth and usually appears between 20 to 30 years old, with progressive lens deformation and increasing myopia. Crystalline opacity may occur at the same time as the appearance of the conical lens, occasionally caused by the rupture of the anterior lens capsule.
　　2, Patients may also have many other ocular damages, the most common being the change of pigment in the macula, with yellow or white granules forming around the fovea.

　　Familial hemorrhagic nephritis is a genetic disease, and there are currently no effective preventive measures. However, it should be avoided to prevent infection, fatigue, and pregnancy, and it should be prohibited to use nephrotoxic drugs.

　　The diagnosis of familial hemorrhagic nephritis relies not only on symptoms but also on auxiliary examinations, which are indispensable methods. The commonly used clinical examinations are as follows:
　　One, Urine Examination
　　Patients have hematuria and proteinuria. Male patients manifest persistent hematuria, and initially, there is only trace proteinuria, which increases with age and often develops into nephrotic syndrome proteinuria. Changes such as increased blood urea nitrogen and creatinine levels may occur when renal function failure occurs.
　　Two, Light Microscopy Examination
　　There is no specificity of renal lesions under the optical microscope. In the early stage of the disease, glomerular lesions are roughly normal, with only slight focal segmental mesangial tissue proliferation. As the lesions progress, glomeruli gradually develop into glomerulosclerosis; in the late stage, glomeruli appear fibrosis and spheric hardening, and the renal interstitium can develop from inflammatory cell infiltration to fibrosis, accompanied by tubular atrophy.
　　3. Electron microscopy examination
　　The ultrastructural changes of the glomerular basement membrane (GBM) are of diagnostic significance for this disease and occur earlier than those observed under an optical microscope. If thickened GBM is widely present and interspersed with thinning GBM, it is of great significance for the diagnosis of the disease. Pure GBM thinning without GBM thickening is more common in benign familial hematuria, i.e., thin basement membrane nephritis.
　　

　　In addition to conventional treatment, dietary adjustment is also required for familial hemorrhagic nephritis. Common dietary requirements are as follows:

　　1. Low-salt diet. When clinical symptoms such as hematuria, proteinuria, edema, and hypertension appear, salt should be avoided in the diet. Because eating too much salt increases sodium, which increases the concentration of electrolytes in the human body tissues, and when sodium concentration increases, it is an important cause of edema. Therefore, patients with kidney disease must avoid salt. When there is edema and the urine output is low, in addition to taking medication, some diuretic foods can be chosen. For example, winter melon has the effects of diuresis and thirst.

　　2. Eating fresh fish and soybean products. Patients with kidney disease continuously lose protein from urine, so they must supplement it from food. Generally, when plasma protein is lower than normal, high-protein foods such as fish and eggs can be increased. However, when the blood non-protein nitrogen level increases, low-protein foods should be selected. For example, drinking some fish soup, as 70% of the protein in fish is in the meat, eating fish soup can not only supplement nutrition but also promote diuresis and reduce swelling.

　　Familial hemorrhagic nephritis is a genetic mutation, and there is currently no effective treatment. However, infection, fatigue, and pregnancy should be avoided, and nephrotoxic drugs should be prohibited. If the patient already has hypertension, it should also be actively controlled. When the patient progresses to end-stage renal failure, dialysis or kidney transplantation can be performed.
　　In recent years, with the increase in kidney transplant patients, it has been found that about 10% of male patients can develop antibodies after transplantation (especially in the first year). Therefore, it is recommended that patients closely monitor urine routine, renal function, and serum antibodies for one year after kidney transplantation. If antibodies are produced, plasma exchange, corticosteroids, and cyclophosphamide should be used for intensified treatment, but the efficacy is often poor, and it is often necessary to remove the transplanted kidney. If the anterior spherical crystalline lens seriously impairs vision, consider lens extraction and artificial crystalline lens implantation.