Read the text and describe how to help children with growth problems.

Medical experts say there are at least 100 causes of growth disorders in children: kidney problems, genetic disorders, thyroid or pituitary glands that do not work correctly, emotional problems, a lack of good food, heart valve disorders. Whatever the cause, growth disorders are serious. They may be linked to other medical problems. Or they may be a cause of mental problems as the child grows older.

Experts say that all children with growth problems can be helped. Parents, friends and teachers can provide important emotional support, even if the growth disorder cannot be treated medically. And research teams have found a number of ways to treat many different growth disorder problems.

When a child grows too slowly, the pituitary gland should first be checked. This is because the pituitary produces the hormone that controls the rate at which the body grows. If too little hormone is released, a child does not grow enough. Such a disorder of the pituitary gland is responsible for only a small percentage of growth problems, however. But it is one that can be treated.

Researchers now use the techniques of genetic engineering to produce large amounts of growth hormone in the laboratory. They transplant genes for growth hormone into the common bacteria Eschericia coli. The bacteria with changed genes, reproduces rapidly, making large amounts of the growth hormone. Researchers say the synthetic growth hormone helped about 40 percent of the unusually short children who received the substance in early tests.

Doctors admit, however, that the majority of children with growth disorders cannot be treated, even with unlimited supplies of growth hormone. This is because the majority of unusually short children have a problem that has nothing to do with the hormone. Most of them have a genetic disorder that interfered with the normal development of their bones. Many of them are not just short. Instead, different parts of their bodies grow at different rates. For example, child may have extremely short arms and legs and a short body, but a large head. Such disorders cannot be treated until researchers learn how to fix the damaged genes or to provide missing enzymes.

One kind of growth disorder that can be treated is called renal tubular acidosis, or RTA. It is a failure of the kidneys to remove enough acid from the blood. RTA is hereditary. But it also can begin for no clear reason.

Doctor Elisabeth McSherry of the University of California discovered that large amounts of bicarbonate of soda, common baking soda, could treat RTA successfully. It greatly reduces the amount of acid in the blood. Doctor McSherry and other researchers warn that large amounts of baking soda should not be given to children unless they suffer from RTA. Bicarbonate of soda could cause muscle cramps, kidney stones and breathing problems in children who have normal amounts of acid in their blood. The treatment should be given only under the direction of a doctor.

Another kidney disorder, a childhood kidney insufficiency, affects bone growth in children. Doctors know that vitamin D helps the body to use calcium and phosphorus, two important bone-building chemicals. But the vitamin must be changed, first by the liver and then by the kidneys, before it can do this. Childhood kidney insufficiency prevents the necessary change in vitamin D. And so the calcium and phosphorus cannot be used completely. Children suffering from this kidney disorder usually are very short. Their bones grow slowly. Their legs are not straight. And they often have bone pains. Some cannot walk.

Scientists at the University of Wisconsin found a way to help these children. They produced vitamin D in its active form. It is the same kind the child`s body would have produced if the kidney had worked as they should. The body can use it directly to help build strong bones. The scientists gave the new vitamin D to a group of children suffering from childhood kidney insufficiency. It cured the disease and stopped the pain. The children were able to walk and run again. And they grew three times as fast as they had been growing.

Some children do not grow normally because they do not eat very much. Some chemical imbalance seems to turn off their hunger signals. They just do not feel hungry. Some of these children can be helped by the drug cyproheptadine. Doctors at the Hospital for Sick Children in Toronto, Canada, tested cyproheptadine on children with poor appetites. They gave them the drug for three months. During this time, the children started eating so much that they gained five times as much weight as normal.

Some children do not grow normally because they do not get enough zinc. Zinc is an element which is present in the body in very small amounts. It is found in most protein foods, such as meat, milk, fish and eggs, and in whole grains. Yet some persons do not get enough. A lack of zinc can affect the sense of taste, cause wounds to heal slowly, and prevent normal sexual development. Doctors at the University of Colorado Medical Center tested a group of children who had less than one-half the normal amount of zinc for children of their age. Fifty percent of these children could not taste normally. Seventy percent had never felt like eating much. Eighty percent had growth problems. Doctors at the medical center gave small amounts of zinc to eat of these children. They could taste normally again.

A chemical imbalance in the thyroid gland also can prevent children from growing. Doctors at the University of Marylnd found a drug that seems to help them. The drug is called levothyroxine. It is a thyroid hormone produced in the laboratory. The doctors gave the drug to a group of children who had thyroid disorders. The children grew from seven to 12 centimeters during the first year of treatment, and from five to eight centimeters during the second year. Levothyroxine also helps children suffering from pituitary disorders.

Doctors say that emotional problems also can cause growth disorders. A child may suddenly stop growing because of stress, from being sick or perhaps from reaction to a family problem. Such a growth disorder is temporary. The child will start growing again as suddenly as he stopped, just as soon as the cause of stress is removed.

Doctors also note that most growth hormone is produced during sleep. This means that a child with serious sleeping problems may not grow normally. However, normal growth would return once the sleeping problem is solved.

Doctors say that some growth disorders are apparent at birth. Others may not be noticed for years until the child galls behind normal growth rates. So growth experts urge parents to measure a child at least once every year. Children grow at different rates, of course. Most girls grow faster than boys, and they stop growing sooner. And every child grows at a different rate each year. But generally, experts say, a child grows five centimeters or more each year. They say parents should talk to a doctor if a child`s yearly growth falls below five centimeters.