Congenital patellar dysplasia

The occurrence of many diseases is related to congenital factors, and some diseases are not easy to treat, so pregnant women should strictly follow the doctor's requirements for prenatal checkups during pregnancy, so as to detect and solve them early. Congenital patellar dysplasia may not be accurately diagnosed during prenatal examination. The symptoms of this disease will become more obvious during adolescence, and various complications often occur.

patella

1. Renal manifestations More than half of the patients with nail-patella syndrome have no obvious clinical renal manifestations. In patients with clinical renal manifestations, the characteristic presentation is that of a benign renal disease, with the most common symptoms being varying degrees of proteinuria, microscopic hematuria and cystic urine, edema, and hypertension. In one study, 56% of patients had abnormal precipitates in their urine, impaired urine concentrating ability, and abnormal urine acidification or protein secretion. 30% of people with kidney involvement will slowly develop renal failure and die from uremia.

2. Damage to bones and nails The nail abnormalities in this syndrome include discoloration, spoon-shaped nails, longitudinal ridges, nail loss or nutritional disorders, and triangular nail arc shadows. These findings are usually symmetrical and present in 80% to 90% of patients. Fingernails are more likely to be affected than toenails, with the thumb being most frequently affected. The patella is absent or hypoplastic in approximately 60% of patients. These changes may be associated with lateral lowering during joint flexion, resulting in a valgus knee deformity. Patellar abnormalities can also lead to osteoarthritis, osteoarthrosis, and joint effusions. 80% of patients with this syndrome have an open iliac crest that protrudes forward and upward, which is called the iliac angle. Abnormalities of the elbow include dysplasia and distal humeral protrusion, resulting in an increased carrying angle and limited extension and supination function. Some cases are accompanied by radial head hypoplasia and radioulnar joint abnormalities.

Among the above manifestations, absent or underdeveloped fingernails or toenails, absent or underdeveloped unilateral or bilateral patellas, retropatellar spurs, and valgus deformities of the elbows and ilium are collectively referred to as the nail-bone tetrad.

3. Others In addition to glomerular basement membrane defects, radiological examinations revealed other structural abnormalities in the kidneys and urinary tract of this syndrome, including: calyx dilatation and cortical scarring, suggesting vesicoureteral reflux; unilateral renal atrophy combined with bilateral ureters and bilateral calyces; unilateral renal dysplasia and contralateral bilateral kidneys; calyx blunting and kidney stones.

The main diagnostic basis for this disease is family history, and the typical clinical manifestations are bone X-ray signs and proteinuria. Renal biopsy was performed if necessary.

Clinically, it is more common in adolescents. The main manifestations of kidney damage are proteinuria, microscopic hematuria, edema and hypertension, and occasionally nephrotic syndrome. The course of the disease is relatively benign, and only 10% of patients develop renal failure in the late stage. Extrarenal manifestations include nail dystrophy, unilateral or bilateral patellar agenesis, elbow deformity, angular pelvis, and other skeletal abnormalities. Most cases of this disease attract attention due to difficulty in walking caused by patellar deficiency. It can be diagnosed based on typical skeletal changes and can be confirmed if accompanied by kidney damage. Radiographic examination shows characteristic changes in the iliac angle, which has clear diagnostic significance.

A small number of patients have been reported to have ultrastructural changes in the glomerular basement membrane without bone, skin, nail, or other typical manifestations of this syndrome; these patients are considered to have abortive or single nephrotic variants of the syndrome. But the electron microscope images published by these studies do not strongly support this view.

The glomerular basement membrane moth-eating phenomenon alone cannot be used to judge the renal biopsy specimen. Phosphotungstic acid staining must be used to identify the fibrils. Because of its higher sensitivity, it is more valuable for diagnosis.