Nail-patella syndrome

Introduction to nail-sacral syndrome A nail-to-sacral syndrome (nail-patellasyndrome) or hereditary bone-to-finger dystrophy (hereditary osteo-onyx dysplasia), a hereditary disease characterized by dysplasia or loss of the tibia (toe) nail dystrophy, elbow dysplasia, sacral horn and renal failure. basic knowledge The proportion of illness: this disease is rare, the incidence rate is about 0.0003%-0.0005% Susceptible people: no specific population Mode of infection: non-infectious Complications: vesicoureteral reflux kidney stones

Nail - the cause of tibial syndrome

(1) Causes of the disease

The syndrome is autosomal dominant, and the locus is linked to the adenylate cyclase and ABO blood group on chromosome 9.

(two) pathogenesis

At present, little is known about the pathogenesis of this syndrome. Some people think that it is a collagen disease. There are abnormalities in the synthesis, assembly or degradation of collagen. The cytological mechanism of this disease has not been studied. The pathological changes lack non-glomerulus. The damage of the basement membrane suggests that the various damages in this syndrome may be due to different mechanisms. Not all lesions are associated with basement membrane abnormalities. A few patients develop anti-glomerular basement membrane nephritis and support glomerular basement membrane components. The hypothesis of abnormality, using a monoclonal antibody against the Goodpasture epitope, found that the glomerular basement membrane of renal biopsy specimens in 2/3 patients did not bind to the monoclonal antibody, suggesting this There is some degree of heterogeneity in the basement membrane component of the syndrome, which also suggests the presence of Goodpsture antigen deletion or alteration. It is worth noting that it is the primary or the success of this syndrome. Change.

Nail-sacral syndrome prevention

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Nail-sacral syndrome complications Complications of vesicoureteral reflux kidney stones

Common ureteral ureteral reflux; renal pelvis becomes dull and kidney stones, posterior tibial bone spurs, elbow and humeral deformity, etc., even with iris pigment abnormalities.

Nail-Sacral Syndrome Symptoms Common Symptoms Loss of the humerus or dysplasia refers to (toe) nail loss joint deformity horny arc shadow kidney involvement tubular urinary joint dysfunction humeral head dysplasia light pressure nails, fingers... finger congestion

1. More than half of the patients with nail-sacral syndrome have no obvious clinical manifestations of the kidney. In patients with clinical renal manifestations, the characteristic manifestations are benign nephropathy. The most common symptoms are different degrees of proteinuria, microscopic hematuria and cast. Urine, edema and hypertension, a study found that 56% of patients with abnormal urine in the urine, urinary enrichment ability, uric acid or protein secretion abnormalities, 30% of kidney involvement will slowly develop into kidney failure, died in Uremic disease.

Meyrier et al reported two families showing the diversity of progression of kidney disease. One family, a 64-year-old male patient, had proteinuria for 20 years, with only mild insufficiency in kidney function, and his brother died at the age of 25. In renal failure, one of the twins of another family gradually develops into end-stage renal failure, while the other long-term only proteinuria, the literature shows that the degree of ultrastructural damage seems to be related to the severity of the clinical manifestations and the course of the disease. The relationship is small; the number of kidney stones is not equal to the number of congenital urinary tract malformations.

2. Skeletal and nail damage The syndrome is characterized by discoloration, spoon-shaped nails, longitudinal warts, finger nail loss or nutritional disorders, triangular nail shadows, which are often symmetrical. In 80% to 90% of patients, nails are more susceptible to nails, and the frequency of thumb involvement is the highest. About 60% of patients have humeral loss or dysplasia. These changes may be related to the lateral reduction of joint flexion, which may lead to knee valgus deformity. Abnormal humerus can also lead to osteoarthritis, osteoarthrosis and joint effusion. 80% of patients with this syndrome have patella stenosis, protruding forward and upward, called humeral horn, abnormal elbow including dysplasia, distal humerus The posterior process leads to an increase and extension of the lifting angle, and the function of the supination is limited. Individuals are associated with dysplasia of the humeral head and an abnormality of the ankle joint.

In the above manifestations, the nail is missing or underdeveloped, the unilateral or bilateral humerus is missing or dysplasia, the posterior tibial bone spur, the elbow and the humeral deformity are called the nail-bone quadruple syndrome.

3. In addition to glomerular basement membrane defects, radiological examination revealed other structural abnormalities in the kidney and urinary tract of this syndrome, including: pyelectasis and cortical scars, suggesting vesicoureteral reflux; unilateral nephrotic condensation and double Ureter and double renal pelvis; unilateral renal dysplasia and contralateral kidney; pyelectasis and kidney stones.

Nail-sacral syndrome examination

There may be different degrees of proteinuria, microscopic hematuria and tubular urine, decreased urine concentration, abnormal uric acid or protein secretion, 30% of kidney involvement will slowly develop into renal failure, and there may be uremia changes in renal failure.

1. Light microscopy has a considerable variability in glomerular performance under light microscopy. Patients without renal dysfunction usually have normal or near normal glomeruli. In some typical cases, some capillary basement membrane thickening can be seen. , but not ubiquitous, can also see global or focal glomerulosclerosis, which is related to the level of renal dysfunction, especially the degree of proteinuria, suggesting the role of proteinuria in the progression of renal damage in this syndrome Others may have epithelial cells and endothelial cells, accompanied by crescentic glomerular basement membrane disease, crescents, tubule atrophy and interstitial fibrosis parallel to the degree of renal dysfunction, arterial intimal fibrosis, arteriole glass Change, etc., often indicates the presence of high blood pressure.

2. Immunofluorescence examination Because the syndrome is not immune-mediated, glomerular immunohistochemistry results are often negative, in the global or segmental glomerular sclerosis, IgM, C3, C1q or three can be observed Both irregular and focal deposition, sediments distributed in the capillary wall or mesangial membrane or both, the distribution is related to the stage and extent of glomerular sclerosis, when other pathological changes are concurrent Immunofluorescence may have a positive finding. In patients with concurrent glomerular basement membrane disease, IgG and C3 are linearly deposited in all glomerular capillaries, and fibrin deposition in capillaries is a form of crescent formation. The association between this syndrome and anti-glomerular basement membrane disease is unclear. It may be that the glomerular basement membrane of patients with nail-to-sacral syndrome continues and severely damages the glomerular basement membrane. The antigenicity leads to antibody production, and Mackay et al. reported a case of nail-sacral syndrome with membranous glomerulonephritis, showing uniform granular IgG deposition on all capillary walls.

3. Ultrastructure The ultrastructure of the glomerular basement membrane is different regardless of the glomerular performance of the patients under the light microscope and the clinical presence of renal symptoms such as proteinuria.

Common and characteristic lesions are ultrastructural abnormalities of the glomerular basement membrane, and a large number of patchy translucent substances are seen in the whole layer of the basement membrane. This kind of thing is sometimes seen in the mesangial matrix, which is called Characteristic "moth" performance, stained with standard lead citrate, sometimes found in the glomerular basement membrane and mesangial matrix, crude fibrils and cross-banded collagen, stained with phosphotungstic acid, The substance is more common, the fibrils are small clusters, located in the glomerular small segment of the basement membrane, or distributed along the entire glomerular basement membrane, the thickness of the glomerular basement membrane is not uniform, in the same capillary wall The thickness can vary from normal to thickening. In the thickened part of the glomerular basement membrane, the translucent band is more and more prominent, and the mesangial matrix is also increased. In some cases, translucent is visible. Substance and collagen fibers, non-small basement membrane of the kidney, no translucent and collagen-like fibrils, changes in the basement membrane of the renal tubules were chronic tubulointerstitial nephropathy-like lesions, consistent with glomerular damage in the late stage.

In most cases, there is no electron dense deposit, and the glomerular visceral epithelial cells often decrease or disappear, and the degree of reduction is related to the severity of proteinuria.

Diagnosis and differentiation of nail-sacral syndrome

The main diagnosis of this disease is family history. The typical clinical manifestations are X-ray signs of bone and proteinuria, and renal biopsy is performed if necessary.

Clinically more common in adolescents, the main manifestations of kidney damage are proteinuria, microscopic hematuria, edema and hypertension, occasionally nephrotic syndrome, relatively benign course, only 10% of patients enter the kidney failure late, extrarenal manifestations of nails Nutritional disorders, lack of one or bilateral humerus, elbow deformity, angular pelvis and other skeletal abnormalities. Most of the disease is caused by difficulty in walking due to lack of humerus. It can be diagnosed according to typical bone changes, accompanied by kidney damage. More can be diagnosed, radiological examination showed that the humeral angle is a characteristic change, with a clear diagnostic significance.

It has been reported that a small number of patients have ultrastructural changes in the glomerular basement membrane without bones, skin, nails, and other typical manifestations of this syndrome. These patients are considered to be the type of frustration or single nephropathy of the syndrome. However, the electron micrographs published by these institutes do not strongly support this view.

Judging the renal biopsy specimens can not only use the glomerular basement membrane moth phagocytosis, and it is necessary to identify the fibrils with phosphotungstic acid staining, which is more valuable for diagnosis because of its higher sensitivity.

It should be differentiated from other diseases that cause kidney damage and bone disease.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.