Traditionally, children with WS have trouble keeping up with the typical growth charts that pediatricians use. In fact, for many infants, this may be the first sign of the syndrome. Many infants with WS will be low in weight, experience longer than average colic and have trouble nursing. These symptoms will often serve as a red flag that there is a larger issue at hand and could eventually lead to genetics testing and a diagnosis.
Individuals with WS tend to have low growth in utero (or during pregnancy) and have a low birth weight. Ask many parents who have a child with WS and you'll find they actually wear out their clothing in their early years. Because of slow growth, individuals with Williams syndrome should use a modified growth chart for WS. A typical chart should also be used for comparison and to map their growth curve. The rate of growth, which is graphed on a growth chart, is always a better indication of health than their placement at any given time on the chart. People are genetically built different- it's hard to compare a greyhound's growth to a St. Bernard and the same holds true for someone who is born petite to another who is genetically larger in stature. Therefore, if the rate of growth follows the expected pattern, the child should be considered healthy. In WS, expect your child to be smaller in height and weight and use the WS charts to determine that they are within a healthy range rather than the typical growth chart. Use the following link to access the growth charts from the American Academy of pediatrics.
*Just a note about the charts- there isn't a separate infant growth chart for WS in the US like there is for the typical charts, emphasizing the importance of using a typical chart at the same time to get a good accurate picture of their overall growth.
Trouble growing in adolescence
Adults with WS tend to be smaller in stature due to slow growth during early childhood and an early onset of puberty. Studies show that about 90% of females with WS and 83% of males reach puberty around the age of 12, which is considered early.
The onset of puberty is controlled by the pituitary gland in the brain. The pituitary gland is a master endocrine gland that controls growth of the sexual organs during development as a fetus and as a teen. Two hormones are released by the pituitary- FSH and LH. These hormones travel through the blood stream and talk to the sex organs (ovaries for females and testes for males).
Failure to Thrive
Many children with WS will have what is called failure to thrive. Failure to thrive is used by medical professionals to identify children who are not growing at what is considered typical. If a child falls below 3% in height or weight, they will be described as failure to thrive. There are many reasons why children can fall into this category, WS being one of them. From there, it is important to access the child's health and diet to rule out any deficiencies they may have.
There are some issues common in WS that can make growth an even larger issue. These include calcium imbalance, reflux, poor nursing due to low tone, colic, poor diet due to sensory issues, and larger issues such as serious heart and endocrine imbalance. Therefore, it is important for a doctor to monitor your child in a preventive manner to rule out these issues and help them grow as optimally as their genetics will allow.
Colic is defined as intense episodes of crying by an infant that lasts more than 3 hours, 3 days a week for 3 weeks. Any parent who has experienced this knows it does a number on your mental and physical strength and can lead to bigger problems of sleep deprivation and depression. Usually the colic is accompanied by gas and abdominal bloating. Often the gas will increase as the baby cries because they swallow air. WS infants tend to experience colic in a different way than a typical infant. The colic often starts later than average, around 4 months of age and can last until 10 months, in contrast to average colic lasting from 1 to 4 months of age. Although colic is somewhat of a mystery in the medical world, there are some issues that should be checked because they are associated with it in the WS world. These include, reflux* and hypercalcemia (see below). They could also be connected to sleep issues* and potential food allergies*. About 10% of colic sources are associated with food intolerance, milk being the leading culprit. Changes to diet, one week at a time, may pinpoint a dietary cause of the colic. (We found milk was the source of our daughter's colic symptoms). The source of colic remains a mystery for most, but if your child has these symptoms, it's smart to check for the potential causes. If some of these are real problems they could reduce or eliminate the symptoms completely, saving you and your little one a lot of sanity!
*Stay tuned for future blog posts on these topics!
Some individuals with Williams syndrome can have trouble managing calcium levels in their bodies. They tend to have high levels of calcium which can lead to hypercalcemia (high calcium in the blood) during infancy and hypercalcuria (high levels of calcium in the kidneys) during adolescence and adulthood. The cause of this is not really understood. Many researchers think it ties to some sort of Vitamin D metabolism issue, but it is still a big mystery.
Vitamin D helps your body absorb calcium and can enter your body through food and by the sun. Naturally, most foods are not very rich with vitamin D. Traditionally, most people get vitamin D from the sun. In fact some people can get the same amount of vitamin D from 10 minutes in the sun as the amount you'd get from drinking 10 glasses of milk. The time you need varies based on your skin coloring- fair skinned people need less exposure, dark skin need more. But, overall the sun is a better source of vitamin D. You don't see this much in the media because of all the skin cancer scares, but small amounts of sun exposure without sunscreen can actually be healthy. In today's world where we spend more time indoors than out, medical professionals are seeing more and more issues with people being deficient in vitamin D. Therefore, our food industry has enriched foods with vitamin D and calcium. You find it added to most dairy, such as cheese, milk and yogurt. You can also find it in fatty fish such as salmon and some grains are enriched with it such as cereals and bread and it is even added to your orange juice.
How does the sun give you vitamins?
When the sun's rays hit your skin, they are absorbed and chemically change a cholesterol that is stored in the skin. The sun changes that cholesterol to vitamin D. The vitamin D is then absorbed into the blood stream that is in the lower layers of skin. From there, it joins any vitamin D you ate or drank and travels to the liver where it is changed again into a more usable form. At this point the vitamin D can either be used by the kidneys or stored in fat deposits. The route it takes is determined by your endocrine system.
The endocrine system is a regulator. Think of it like a giant switch operator with lots of balancing acts to keep track of. When something in your body is thrown off balance, the endocrine system flips on a switch that releases a hormone. That hormone will travel through your blood and deliver a message to a cell or organ in your body designed to restore equilibrium. When the body is back in balance, the switch is flipped off and things go back to normal. This process is called negative feedback.
Calcium regulation works on a negative feedback loop. When your body is in need of calcium, the parathyroid (or switch operator) in the neck releases a hormone called PTH that talks to the kidneys. The kidneys then take the vitamin D that was modified in the liver and changes it into a hormone. That newly modified vitamin D is delivered by the blood to an organ that needs calcium- it may go to cells in the digestive system, bone, muscle or nervous system. The vitamin D acts like a bouncer at a nightclub. It'll latch onto a receptor or doorway on the cell where it opens up the gates to let calcium inside to be used. Therefore, the presence of vitamin D in the body is how your body maintains calcium balance.
High calcium during infancy
In 15% of infants with WS, calcium levels become very high in the blood stream. This is called hypercalcemia. Classic hypercalcemia is traditionally an issue with the parathyroid hormone (PTH), where the switch isn't working properly, but studies have shown that in WS children with hypercalcemia there is no abnormal levels of PTH. Therefore, hypercalcemia in children with WS is called idiopathic, which means it has an unknown cause- the switch works fine and something else goes wrong in the circuit. What goes wrong, we don't know.
Although researchers don't understand the cause, they are aware of the effects. Signs of hypercalcemia are very colic-like; irritability, vomiting, constipation and muscle cramping. If these signs are present in an infant with WS, it is important for their calcium levels to be monitored by a specialist such as a nephrologist (specialist who monitors the functioning of the kidneys).
Testing calcium levels
When the calcium levels are checked, it is important for the blood serum levels to be measured as well as urine levels. This will give the specialist a good picture of the vitamin D synthesis and calcium regulation occurring in the body. Specialists will want to look at the levels of calcium in the blood and compare them to the amount of creatinine. Creatinine is created when the muscles use calcium to contract. This can be monitored with a blood sample. A serum calcium test and serum creatinine test will be run. Serum calcium and serum creatinine tests should be taken during infancy, usually at the time of diagnosis. Even if there is no sign, it's useful prevention to see what the levels of blood calcium are. This can be used as a baseline to compare to later and it can be a warning flag if levels are approaching high levels. After the initial test, it is recommended they be tested again at 24 months and annually after the age of 5.
Doctors will also be interested in monitoring how well the kidneys are maintaining calcium balance. This can be assessed in a urine sample. Urine will be collected and tested for calcium-creatinine ratio. When there is too much calcium in the body, high levels will be excreted by the kidneys in an effort to restore some balance. This urine test shows the ratio of how much calcium is excreted to how much is being used (assessed by the amount of creatinine waste). This is tested by simply collecting a urine sample. This test should also be ran at diagnosis, at 12 months, 3 years and once between the age of 5-13 and once again between 14-20. Refer to the following medical supervision chart for this information.
But, how can they collect urine from a baby?
If your infant is being tested, they will give you a bag with an adhesive portion. You stick the bag to your infant and a diaper can go over it. If the adhesive sticks, it will collect the urine. Sometimes, it takes a few tries to get this to work because the baby will often wiggle out of it. (Parents of infants- when you schedule this test, be prepared to spend a lot of time at the hospital waiting for your child to pee or
schedule a time to do this at home and drop off a sample the following day. You'll want to take a few of the adhesive bags in case you need to try multiple times).
How can I manage my child's calcium and vitamin D intake?
If your child is diagnosed with hypercalcemia, the doctor will guide you on how to change their diet to manage the disorder. Many infants in the WS world end up using Calcilo formula. This formula, as the name implies, has a very low amount of calcium in the mixture. Parents should be careful not to use this unless they are under a doctor's supervision. Very low levels of calcium in the body are just as dangerous, if not worse. It can lead to rickets or brittle bones, poor growth and even osteoporosis.
The average parent should just monitor their child's diet. Keep their intake of calcium and vitamin D right at 100% daily recommended value, which can be tricky with all the fortified foods. Also, be liberal with sunscreen. These simple changes can prevent calcium levels from becoming too high.
Calcium issues that can occur after childhood
Although the danger of hypercalcemia (elevated calcium in the blood) ends in early childhood, 30% of individuals with WS can have difficulty regulating the levels of calcium and vitamin D throughout their lives. After early childhood and into adulthood, a person with WS can develop hypercalcuria, or elevated levels of calcium in their urine. This can lead to kidney stones (nephrocalcinosis).
As calcium builds up in the kidney, it can crystallize and harden into stones. When these stones become loose, they can block passageways in the kidney that are use to route the urine out of the body. The stone places pressure on the tubes, such as the ureter, sending intense pain messages to the brain. It also will block the urine flow, causing it to back up and place more pressure in the ureter.
You may need to see a dietitian, as well, to monitor diet. It is important for parents to avoid any multi-vitamins that contain vitamin D and calcium as to not aggravate the condition. It's also important to protect your child from sun exposure by using sunscreen. Sunscreen blocks the body's ability to make vitamin D in the skin.
Sources and further reading:
Webinar- Calcium and Vitamin D by Dr. Morris
Hypercalcium and Hypercalcuria in Williams syndrome publication by St. Louis Children's Hospital
Feeding your child with Williams Syndrome publication by St. Louis Children's Hospital
Vitamin D metabolism and the Williams Syndrome clinical studies
Williams syndrome Hypercalciumia study, 2012
High Prevalence of Diabetes and Pre-diabetes in adults with Williams syndrome