Phosphate diabetes: causes, symptoms and treatment

In today's world, almost all parents know about a disease such as rickets. Every pediatrician from the first months of a baby's life warns of the need to prevent this pathology. Rickets refers to acquired diseases that develop as a result of cholecalciferol deficiency, a substance known as vitamin D.

However, in some cases, young children experience symptoms of pathology, despite the observance of preventive measures. In such a case, a disease such as phosphate diabetes should be suspected. Unlike rickets, this ailment belongs to genetic pathologies. Therefore, it is a more serious disease and requires long-term comprehensive treatment.

What is phosphate diabetes?

This is the name of a group of genetic diseases associated with impaired mineral metabolism. In another way, the pathology is called vitamin D-resistant rickets. The dominant type of phosphate diabetes occurs in approximately 1 out of 20,000 newborn babies. The disease was first described in 1937. Later it turned out that there are other genetic forms of pathology. Phosphate diabetes is most commonly found in early childhood. The attention of parents is attracted by impaired gait and curvature of the bones.

Some forms of pathology are accompanied by other metabolic disorders. Sometimes the disease is asymptomatic, and it can only be detected by laboratory tests. The disease is classified with acquired rickets, hypoparathyroidism and other endocrine pathologies. Treatment should be comprehensive from an early age.

Causes of the disease

The main reason for the development of phosphate diabetes is a violation in the genetic structure. Mutations are inherited. Bearers of the pathological gene can be both women and men. Mutation occurs on the X-linked chromosome, which is dominant. In rare cases, phosphate diabetes can be acquired. It develops against the background of tumors of the mesenchymal tissue, which form even in the prenatal period. In this case, the pathology is called "oncogenic rickets."

The disease belongs to the group of tubulopathies - impaired renal function. Due to the fact that the reabsorption of minerals in the proximal tubules is reduced, phosphorus deficiency develops in the body. In addition, the intestinal absorption capacity is impaired. As a result, changes in the mineral composition of bone tissue are observed. Often there is a violation of the function of osteoblasts. Men pass the pathologically altered gene only to their daughters, and women - to children of both sexes. As a rule, in boys the disease is more severe than in girls.

Classification of Phosphate Diabetes in Children

There are several forms of the disease that differ in genetic and clinical criteria. Most often, X-linked hypophosphatemic rickets is diagnosed, which has a dominant type of inheritance. However, there are other varieties of pathology. The classification includes the following forms of the disease:

  1. X-linked dominant type of phosphate diabetes. It is characterized by changes in the PHEX gene, which encodes endopeptidase. This enzyme is responsible for the transport of various minerals through the ion channels of the kidneys and small intestine. Due to a gene mutation, this process slows down, which causes a deficiency of phosphate ions in the body.
  2. X-linked recessive type. It is characterized by a mutation of the CLCN5 gene, which encodes a protein responsible for the work of chloride ion channels. As a result of the defect, the transport of all substances through the membrane of the renal tubules is disrupted. Bearers of this type of pathology can be both women and men. However, the disease develops only in boys.
  3. Autosomal dominant type of phosphate diabetes. It is associated with a genetic mutation on chromosome 12. Due to the defect, osteoblasts secrete a pathological protein that promotes enhanced excretion of phosphates from the body. Pathology is characterized by a relatively mild course, in contrast to X-linked forms.
  4. Autosomal recessive type. It is rare. It is characterized by a defect in the DMP1 gene located on chromosome 4. It encodes a protein responsible for the development of bone tissue and dentin.
  5. Autosomal recessive type, accompanied by the excretion of calcium in the urine. It occurs due to a defect in a gene located on chromosome 9 and responsible for the operation of sodium-dependent renal channels.

In addition to the listed forms of phosphate diabetes, there are other types of pathology. Some varieties of the disease have not yet been studied.

Differences between Rickets and Phosphate Diabetes

Rickets and phosphate diabetes in children are not exactly the same thing, although the clinical picture of the disease is almost identical. Differences between these pathologies in etiology and the mechanism of development. Ordinary rickets is an acquired ailment associated with a lack of cholecalciferol. This substance is formed in the skin under the influence of sunlight. It is customary to take a diagnostic dose of vitamin D daily for all children from 1 month to 3 years old, excluding the summer period. Due to cholecalciferol deficiency, the process of calcium absorption is disrupted. As a result, bone deformation develops.

The difference between phosphate diabetes is that it refers to congenital diseases. With this pathology, the absorption of minerals in the kidneys, in particular phosphates, is impaired. In some cases, calcium deficiency is noted. Due to a violation of the mineral composition of bone tissue, the symptoms of pathologies are similar. The difference between them can be established only after laboratory diagnostics.

Hypophosphatemic rickets in infants: symptoms of the disease

Symptoms of the disease are usually diagnosed in the second year of life. In rare cases, hypophosphatemic rickets in infants are observed. Symptoms that can be diagnosed in infancy are muscle hypotension and shortening of the limbs. The main clinical manifestations are:

  1. Deformation of the joints of the legs.
  2. O-shaped curvature of the lower extremities.
  3. Growth retardation in children - becomes noticeable after 1 year.
  4. Thickening of the wrist joints and costal cartilage - "rickety bracelets and rosary."
  5. Pain in the pelvic bones and spine.
  6. Damage to tooth enamel.

Most often, the main complaint of parents is that the baby has bent legs. When the disease progresses, bone softening occurs - osteomalacia.

Diagnosis of phosphate diabetes and rickets

To identify the pathology, a study of the biochemical composition of the blood is carried out. In this case, hypophosphatemia is noted. The calcium level in most cases is normal, sometimes it is reduced. During the height of rickets, an increase in alkaline phosphatase is noted. Radiography reveals osteoporosis and a violation of bone growth zones. Urine contains a large amount of phosphate. Calciuria is sometimes observed.

Treatment of rickets and phosphate diabetes

Large doses of cholecalciferol are used to treat phosphate diabetes. In some cases, calcium preparations are indicated. Be sure to use medicines containing phosphorus. To improve the condition, vitamin and mineral complexes are prescribed. These include preparations "Vitrum", "Duovit", "Alphabet", etc.

With severe curvature of the bones, physiotherapeutic treatment, exercise therapy and surgical intervention are indicated. Consultation with an orthopedic surgeon is required.

Preventive measures and prognosis

The preventive measures include examinations of a pediatrician and surgeon, walks in the fresh air, the appointment of vitamin D from the first month of life. If there are phosphate-diabetes patients in the family, a genetic study should be performed during fetal development. The prognosis is most often favorable with timely treatment.

Family and non-inherited rickets: similarities and differences

With diabetes, phosphate diabetes combines common symptoms and the fact that it breaks the metabolism. With rickets - the fact that it leads to abnormal bone development, and this is due to impaired metabolism of phosphorus and calcium. Phosphate diabetes in children resembles a disease that occurs when there is a lack of vitamin D in food, in adults it happens much less often and is manifested by softening and bending of bones - osteomalacia. Its other names are vitamin D-dependent rickets, hypophosphopenic rickets, familial congenital rickets, type 2 rickets.

What exactly happens in the body with this disease? In order for phosphorus and calcium to be absorbed correctly, and from which strong bone tissue is formed, vitamin D is first needed. When it enters the body with food, it is converted into special hormone-like substances.

Just as insulin helps cells absorb glucose from the blood, vitamin D derivatives allow them to absorb phosphorus and calcium. And in the same way as in diabetes mellitus, insulin production or cell sensitivity to it is disrupted, in phosphate diabetes the process of production of substances necessary for the body from vitamin D is disrupted or tissue sensitivity to these substances decreases. Not absorbed by the bones, calcium remains in the blood, and phosphorus is washed out with urine.

The effects of diabetes phosphate also resemble those that occur without treatment for rickets. The child grows, the bones of his skeleton continue to bend, and in severe cases, he loses the ability to move independently.

Disability also threatens adults with a sporadic, that is, non-hereditary form of the disease - phosphate diabetes complicates the course of the underlying disease that caused it.

Symptoms and Diagnosis

In children, the need for phosphorus and calcium is much higher than in adults, so the consequences of the disease are harder. According to the main symptoms, phosphate diabetes coincides with rickets. In particular, these are:

  • unstable duck gait,
  • curvature of the lower legs with the letter O,
  • below normal growth
  • curvature of the spine.

At an early age, phosphate diabetes is often detected after parents notice that the baby does not move much. Some children cry and act up when they are forced to walk - their bones hurt. With rickets, the bones become brittle, so even if the curvature is not yet visible, the disease can be suspected in those children who often have unexplained causeless fractures.

But there is a difference between the symptoms of classic and hereditary rickets. Normal rickets appears during the first months of life, hereditary phosphate diabetes - starting in the second half of the year, and sometimes in 1.5-2 years, only after the baby begins to walk. In this case, the lower limbs (long tubular bones), knee and ankle joints are bent primarily.

Correctly diagnosed blood tests for biochemistry and x-ray studies help. The biochemical parameters of blood and the structure of bone tissue in a hereditary familial disease differs from both normal and those disorders that are noticeable with classical rickets. As a rule, when phosphate is suspected of having diabetes in a child, doctors recommend testing to both parents and immediate relatives.

Is it possible to cure family congenital rickets?

The principle of treatment of classic and family hypophosphatemic rickets is the same - the introduction of vitamin D. But since family processing of rickets is impaired, vitamin is needed many times more than in the first case. At the same time, doctors must monitor the levels of phosphorus and calcium in the blood and its other biochemical parameters, individually selecting the right dose.

Vitamin therapy is supplemented with phosphorus preparations (calcium glycerophosphate) and diet, and depending on age, babies are prescribed vitamin complexes, for example, Oxidevit, and foods rich in phosphorus are added to their diet.

Since phosphate diabetes is very similar to rickets of type 1, and sometimes it is not possible to establish a diagnosis right away, doctors advise parents of children under two to three years old to undergo a full examination from time to time. In some cases, drug treatment is not enough, and then the bent bones are straightened by surgical methods. But does the disease itself disappear after treatment?

Just as with diabetes 1 it is impossible to restore the production of your own insulin, it is impossible to “fix” metabolic disorders in diabetes mellitus. But for adults, the amount of calcium and phosphorus that is still absorbed by the body is enough.

Therefore, after adolescence, the disease worsens only during periods of increased need for calcium and phosphorus - in women during pregnancy and lactation.

But the “uncorrected” consequences of rickets - short stature, curvature of the legs - both in women and men remain for life. Women due to deformation of the pelvic bones sometimes have to do a cesarean section.

Symptoms of Phosphate Diabetes

  • This disease is the result of a mutation in the X chromosome, which disrupts the absorption of phosphates in the renal tubules, and subsequently triggers a chain of pathological processes that interfere with the normal absorption of calcium by bone tissue.
  • Men who carry the defective gene pass the disease on to their daughters.
  • Women who carry the defective gene transmit the disease to children of both sexes (and sons and daughters) equally.

Doctor pediatrician will help in the treatment of the disease

Phosphate Diabetes Treatment

  • Prescribing large doses of vitamin D (sometimes for life).
  • Phosphorus, calcium, vitamins A and E.
  • In case of weak (or moderate) deformations of the skeleton, orthopedic treatment is prescribed (for example, correction of curvature of the spine by wearing special orthopedic corsets).
  • Surgical treatment is necessary only with severe deformations of the skeleton. Spend it after the end of the growth period.

Complications and consequences

  • Violation of posture and deformation of the skeleton after phosphate diabetes suffered in childhood are preserved for life.
  • Child lag in mental and physical development.
  • Progression of bone and articular deformities in the absence of adequate treatment can lead to disability.
  • Violation of tooth development (pathology of the structure of enamel, violation of the timing and order of teething, etc.).
  • Hearing loss (as a result of impaired development of the auditory ossicles of the middle ear).
  • The consequence of the disease can be nephrocalcinosis (deposition of calcium salts in the kidneys), which in turn can lead to renal failure.
  • A disease suffered by a girl in childhood can cause pelvic bone deformity, as a result of which a difficult course of labor is likely. At the stage of pregnancy planning, women who have undergone phosphate diabetes in childhood should consult with a specialist about a possible cesarean section.

Prevention of Phosphate Diabetes

  • Early detection of the disease (timely access to a specialist at the first sign of a disease for the purpose of early diagnosis and the appointment of timely treatment: the main objective of these measures is to reduce the risk of complications and consequences).
  • Timely treatment and constant monitoring of children with a similar pathology by a pediatrician and endocrinologist.
  • Medical and genetic counseling for families with phosphate diabetes (where one of the family members suffered this pathology in childhood) at the stage of pregnancy planning.The purpose of this event is to explain to parents the possibility of having a sick child and inform about the risks, consequences, complications of this disease in the child.

Additionally

  • It is known that one of the main chemical elements of bone tissue is calcium. The basis of bone tissue along with calcium is also phosphorus. A person consumes these elements with food.
  • A sufficient amount of phosphates (phosphorus compounds) in the body is one of the necessary conditions for the absorption of calcium by bone tissue.
  • As a result of a mutation of one of the X chromosome genes, phosphate absorption in the renal tubules is disrupted, and subsequently a chain of pathological processes that impede the normal absorption of calcium by bone tissue is launched.

REFERENCE INFORMATION

Consultation with a doctor is required

Lectures on the biochemistry of KSMA, 2004
Volkov M.V., Dedova V.D. Children's Orthopedics-Medicine, 1980

Pathogenesis of the disease

The disease occurs as a result of transmission by a dominant type, which depends on gender. With the disease, enzymatic processes are disrupted, which transform vitamin D into active substances.

Phosphate diabetes develops due to a primary defect in the renal tubules, which are involved in phosphate reabsorption. With too high a percentage of phosphorus excretion together with urine, its amount in the blood of a person decreases, which causes bone deformities.

The main cause of the onset of the disease are mutations of the X chromosome, which disrupt the absorption of phosphates and trigger a whole range of pathological processes that worsen the process of calcium absorption.

Symptoms that indicate the occurrence of health problems that entail the development of phosphate diabetes are as follows:

  • Deterioration in the general condition of the child.
  • Stunted growth.
  • Curvature of the lower extremities in an o-shape.
  • Changes in the ankle or knees.
  • Lower muscle tone.
  • In the back, when palpating, pain appears.

Clinical studies explain the main symptom of the disease in that a person has problems with the development of the musculoskeletal system and deformities of the lower extremities occur. Also, in people with phosphate diabetes, short stature, abnormalities and other structures of the skeleton are traced, the gait changes, pain during movement can be traced.

Doctors can make a diagnosis in the first two years of life, since the pathology develops at a very early age due to a genetic predisposition. With regard to intellectual development, in this case, phosphate diabetes has no effect, however, it still relates to the mental state and manifests itself in the fact that the child understands its dissimilarity with peers, physical limitations.

Types of hypophosphatemic rickets (phosphate diabetes)

Doctors divide this disease into 4 main types:

  • Type 1 appears already in the 2nd year of human life. The main symptoms: stunted growth, there is no hypoplasia of the enamel of the permanent teeth, leg deformities, rickets-like changes in the bones. With this type of disease, phosphate reabsorption decreases and rickets-like changes develop.
  • Type 2 is autosomal dominant, which is not linked to the X chromosome. Appears in the first or second year of life. It manifests itself in the form of curvature of the lower extremities, changes in the skeleton. In this case, the growth process does not change, a person has a fairly strong physique. There are mild symptoms of rickets.
  • Type 3 is manifested in the form of calcium absorption disorders, which lead to the fact that already at the 6th month of life, the child has cramps, hypotension, short stature, muscle weakness and rickets changes in growth.
  • Type 4 occurs mainly in the female in early childhood. It manifests itself in the form of curvature of the lower extremities, tooth abnormalities and rickets in varying degrees.

Complications arising from the disease

Due to untimely treatment, patients with this diagnosis may subsequently receive the following complications:

  • Violation of the spine, as a result - posture.
  • Mental or physical abnormalities in the development of the child.
  • Bone or articular deformities leading to disability.
  • Pathology of the development of the tooth, violation of the time of their development.
  • Disorders in the development of the auditory ossicle.
  • Nephrocalcinosis, which is explained by deposits of calcium salt in the kidney.

If the child has a predisposition to the development of this disease, then his examination begins almost from birth, in order to prevent complications as much as possible. To do this, they check the level of calcium and phosphorus, monitor how the skeleton develops, whether the growth corresponds to the standards that should be at this age.

When the first signs of phosphate diabetes are detected, children are prescribed vitamins. If desired, parents can arrange benefits for the child to receive medicines for free, as well as arrange free trips to special health camps.

Clinical recommendations

Phosphate diabetes is a dangerous disease that develops due to a genetic predisposition, appears in childhood and can cause terrible complications.

As for the recommendations regarding the prevention of the disease, it is possible to exclude the development of this ailment only by careful observation of young families, if such a problem is possible in the family and in the genetic predisposition.

Before conceiving a child, the doctor will prescribe a full examination, after which he will be able to establish the likelihood of a healthy child being born. You can also try to exclude the development of phosphate diabetes with a timely visit to a specialist if his signs began to appear in a child from a young age.

To prevent the development of a terrible disease in a child, it is necessary to strictly follow the recommendations of specialists and timely contact the clinic for diagnosis and treatment. The sooner an adult pays attention to deviations in the usual development of the child, the more the probability of the appearance of the possibility of eliminating many complications increases.

According to official data, indeed, 52% of the country's inhabitants are diagnosed with diabetes. But recently, more and more people turn to cardiologists and endocrinologists with this problem.

Diabetes can also lead to the development of cancerous tumors. One way or another, the result in all cases is the same - a diabetic either dies, struggling with a painful disease, or turns into a real disabled person, supported only with clinical help.

I will answer the question with a question - what can be done in such a situation? We don’t have any specialized program to fight specifically with diabetes, if you talk about it. And in the clinics now it’s not always possible to find an endocrinologist at all, not to mention finding a really qualified endocrinologist or diabetologist who will provide you with quality help.

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Watch the video: Hyperphosphatemia - causes, symptoms, diagnosis, treatment, pathology (March 2020).