21-hydroxylase deficiency

Introduction 21-hydroxylase deficiency is one of the most common types of congenital adrenal hyperplasia, accounting for 90%-95% of the disease. The 21-hydroxylase gene is located in the long arm of human chromosome 6, and the 21-hydroxylase deficiency or deficiency in the body is caused by the deletion of the 21 hydroxylase gene and the conversion of the live mutation. Some patients have different degrees of adrenal insufficiency, and collapse can occur under stress. Hypoglycemia can sometimes occur due to a decrease in cortisol. A small number of pigmentation is aggravated.

Cause

21-hydroxylase is a microsomal enzyme that promotes the conversion of 17-hydroxyprogesterone and progesterone to 11-deoxycortisol and 11-deoxycorticosterone. The reduction or decrease in activity of this enzyme leads to steroid hormones. The synthesis is blocked by progesterone and 17-hydroxyprogesterone levels. Due to the synthesis of androgen, 21-hydroxylase is not required. Under long-term over-stressed ACTH stimulation, a large amount of cortisol precursor enters the androgen synthesis pathway, resulting in elevated androgen levels.

an examination

1. The masculine type is about one-third, and the condition is mild. It has not affected the synthesis of mineralocorticoids, and there are only too many male hormones.

(1) Female pseudohermaphroditism: Female fetuses are overexpressed by androgen. Although their gonads are ovaries, the external genitalia have male deformities. The clitoris is markedly hypertrophied and can be erect, like a penis with severe hypospadias. Infants and pubic hair appear in early childhood, and beards and facial acne can be seen. By puberty, there is no change in female puberty, no menstruation, and flat breasts. The patient's fallopian tubes, ovaries, and uterus were in an undeveloped state.

(2) Male pseudo-precocious puberty: When the male fetus is born, the external genitalia is basically normal, and only the penis is slightly larger. After 1-2 years old, the penis develops fast, can have an erection, and there are pubic hairs appearing, muscles are developed, but the testicles are smaller than normal. Although there is semen, it does not contain sperm.

2. Male mate with salt loss accounted for about two-thirds. In addition to the above masculine manifestations, due to insufficient synthesis of mineralocorticoids, hyponatremia, hyperkalemia, dehydration, hypotension, and increased plasma renin activity were observed. .

In addition, children have abnormal growth and development. When he was born, his body length was normal. After 1-2 years of age, his growth was obviously accelerated. His height and weight were generally higher than that of children of the same age. His hair and muscles were developed. However, since the epiphysis is fused at 12-13 years old and stops developing, the physique in early childhood is higher than that in normal children. In puberty and adulthood, the physique is shorter than normal.

Some patients have different degrees of adrenal insufficiency, and collapse can occur under stress. Hypoglycemia can sometimes occur due to a decrease in cortisol. A small number of pigmentation is aggravated.

Differential diagnosis

1. Cytochrome C oxidase deficiency: It is a kind of Fanconi syndrome, and Fanconi syndrome is a hereditary or acquired disease. Often associated with cystine disease, characterized by abnormal proximal tubular function, causing glucoseuria, phosphate urine, amino acid urine and bicarbonate urine. The disease is rare, more than adult symptoms, renal glucosuria, multiple amino aciduria, hypercalciuria, renal loss of sodium, hypophosphatemia, proximal renal tubular acidosis, hypouricemia, renal tubules Sexual proteinuria, hypokalemia (muscle weakness, soft palate, periodic paralysis, etc.), hypocalcemia (hand, foot and ankle).

2. Trehalase deficiency: one of the clinical classifications of disaccharidase deficiency. This disease, also known as disaccharid intolerance, refers to various congenital or acquired diseases, which makes the intestinal mucosal brush-like disaccharidase deficiency, which causes the digestive and absorption of disaccharide to be disordered. When eating foods containing disaccharide A series of symptoms and signs that occur.

3. Lysosomal enzyme deficiency: The enzymes in the lysosome are all hydrolase, and generally the optimum pH is 5, so they are all acidic hydrolases. If the enzyme in the lysosome is released, the whole cell will be digested. Generally not released into the internal environment, mainly for intracellular digestion. Congenital lysosomal disease is a type of metabolic genetic disease caused by the inadequacy of certain lysosomal enzymes due to mutations in certain genes on the chromosome. Due to enzyme deficiency or enzyme structure defects, the corresponding substrate in the cell can not be degraded and stored, and accumulated in the secondary lysosome, causing cell metabolism disorder, so it is also called lysosomal storage disease. Mucopolysaccharide storage disease is a group of diseases in which acid mucopolysaccharide molecules (aminodextran) cannot be degraded due to lysosomal enzyme defects, resulting in deposition of a large amount of mucopolysaccharide in tissues and increased excretion of mucopolysaccharides in urine.

4, female atypical 21-OHD and polycystic ovary syndrome identification: the latter occurred in women of childbearing age, with high androgenic symptoms and signs, and insulin resistance, B-ultrasound showed multiple ovarian cysts.

5, salt-loss 21-OHD and chronic adrenal insufficiency (hypoadrenocorticism, Addison disease), Addison disease has lost salt, cortisol reduction, sex hormone reduction, no masculine symptoms, and 17-OHP normal.

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