Sotos Syndrome

Sotos is one of the multitude of syndromes, in which height can be one of the symptoms. Its cause is thought to be genetic but, as the chromosome responsible has not been identified, there is no laboratory test to confirm the diagnosis.
First described in 1964, the characteristics which lead toward a diagnosis include accelerated growth, facial characteristics, large hands and feet, poor co-ordination, and developmental delay. To date over 100 families are known to the Sotos Group in the UK, but it must be realised that many children are so mildly affected, that they remain undiagnosed, and live perfectly happy and normal lives. Some parents prefer not to inform schools and friends, in order for the child not to be “labelled”, others will make the condition known, as it can help toward the provision of the proper support, such as physiotherapy, speech therapy, or attendance allowances.

What follows is only the briefest outline of the symptoms which lead to a positive diagnosis. As always, it is important not to view each one in isolation, as they can occur singly, and independently of the syndrome, or as one of a number of symptoms, associated with a totally different condition.

Typically, the baby is significantly larger than average, as a result of excessively rapid peri-natal growth rate. The child will generally have an advanced bone age, so that it will be much taller than its peers. Consequently, a three year old child may be the size and appearance of the average seven year old, but with the behaviour patterns associated with a small child. This can cause embarrassment in a social and public environment. The amount of advancement at the age of five tends to remain constant thereafter.

As is normal, growth stops at puberty. Children with Sotos tend to reach puberty at the low (early) end of the age range. The result is that the final height is not as great as might otherwise have been expected, although they are taller than the height of their parents might have led one to project.

Paradoxically, the Sotos child will not have a simple excess of growth hormone; this could be easily treated. Restricting the final adult height is therefore limited to bringing forward the start of puberty, although one must consider the possible psychological implications due to emotional immaturity. (An alternative is currently on trial, which restricts growth hormone production. Results have yet to be evaluated, and a full licence has yet to be granted. Ed.)

Physical Characteristics

The head is larger than average, and although hydrocephalus (water on the brain) is sometimes suspected, this is rarely the case. The forehead may be broad, and the hairline may start further back than average. Eyes may be further apart, with a slight downward slant at the edges. Jaws may be of slightly different lengths, so that the upper and lower teeth do not meet when the jaws are closed.

The arms are long, and the hands may seem slightly fatty or podgy. Feet are too large, and flat feet are not uncommon. Physiotherapy may be needed to strengthen weak ankles and muscles.

Dental problems are likely to incude poor alignment of teeth, weak enamel, discolouration, first teeth not being pushed out by the secondary teeth, and gum abscesses.

Medical literature describes the children as being clumsy and poorly co-ordinated. Parents who help with excercises designed to strengthen muscles will find that this will improve as a child gets older. Walking is often late with these children, and their balance may seem poor. The weakness of jaw muscles can lead to a drool, and a dislike of anything which needs chewing, meat for example, or sucking, such as a boiled sweet, which may be swallowed whole. Nonetheless, many children display excessive appetite and thirst. (Again, be careful not to judge thirst in isolation. In my experience, most tall people seem to drink more than average. I have my own theory as to the reason, but we can look at that another time. Ed.)

A slight stoop when standing, head jutting forward slightly, and the knees bent, may be observed. Regular physiotherapy, and excercises such as swimming will help to improve this. Unchecked, in the very worst cases, it can lead to spinal problems in later life.

Children may display some insensitivity to pain, for example, having raw blisters on the foot, but not mentioning it, or hands and feet that are blue with cold, but showing no discomfort. The latter is also an indication of poor circulation, which is also not uncommon. In contrast, the scalp can be sensitive, with a great dislike of hair brushing and combing. A tendency to narrow ear canals can increase the chances of ear infections. Many children known to the Sotos Group have had grommets fitted more than once.

Convulsions are not uncommon. Many of these have been described as febrile fits, occuring when the child is ill, and has a very high temperature or fever. The convulsions are controllable with drugs, and most children grow out of them.

The average child affected by Sotos Syndrome will have an IQ at the low end of the normal range. A prediction of the final level of attainment is difficult to make, as it will depend on the amount of support and stimuli, and the quality of education given over the formative years. Concentration is often poor, with the child unable to settle to a task for more than a few minutes. In early schooling this can present difficulties, as the chilldren tend to be large, and so disrupt the classroom when they leave their seats. Language development is significantly delayed in many, but by no means all cases. (Some of the parents I have spoken to feel that this may be due to the poor muscle control in the jaws and tongue. They feel that some of the behavioural difficulties occasionally associated with the Syndrome may be due to frustration caused by the child’s willingness, but inability to communicate clearly. Ed.)

Boys in particular are often very strong, and mothers may be unable to restrain them when they are no more than seven or eight years old. The tantrums usually associated with the “terrible twos” can appear to be more serious, when they are experienced at the age of three, and the child is the size of a seven year old.

A few children experienced bone breakages in the first few months of life, which went unnoticed, being revealed only in later X-rays. One young lady I spoke to who has been affected by Sotos Syndrome told me that this persisted into her teens, when even her dog tugging on its lead was enough to cause a greenstick fracture. The lady in question is now in her early twenties, and living proof that Sotos Syndrome is not the end of the world.

In fact there is very little about the way the Syndrome affects a child that is frightening. The task of the parents in raising the child is hard, yet rewarding. Not one child will display all of the symptoms, and may indeed show only very few. No child will present the parents with all of the difficulties, and certainly not in the same week, month or year.

If you would like further information contact the Child Growth Foundation.