Dr. Marie a Pioneer on DS/Autism

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Down's Syndrome Children with Autistic Features

, M.D.

Down's Syndrome. Papers and Abstracts for Professionals

Volume 9, No. 3, pp. 1-2, July 1986

Reprinted with the permission of , M.D.

Editor, Down's Syndrome. Papers and Abstracts for Professionals

There is virtually no literature describing Down's syndrome children who have

autistic features. Yet everyone who runs a Down's syndrome clinic occasionally

sees a child of this type. This paper discusses an approach to the diagnosis and

treatment of such a youngster.

Down's syndrome occurs in of between 1.0-1.2/1000 live births (Hook, 1982) while

the autistic syndrome occurs between .4-.5/1000 live births (Torrey et at.

1975). Thus both Down's syndrome and the autistic syndrome are among the more

common forms of mental handicaps seen in children.

One of the important questions on evaluating a child is to try and determine

whether both disease entities have occurred coincidentally in this child or

whether this child's autistic symptoms stem from an unusual effect of the

addition of an extra twenty-first chromosome to the child's cells. One example

of the double diagnosis occurs in Down's syndrome children who develop the

infantile spasms syndrome associated with hypsarrhythmia. Patients, Down's or

otherwise, who develop infantile spasms are often left with autistic features.

Clinical Delineation of a Child with Both Syndromes

To start with, it is necessary to define a Down's syndrome child with autistic

features. Such a child can be diagnosed if the child, in addition to having a

Trisomy 21 chromosomal karyotype (or one of the other chromosomal variants that

result in the phenotype of Down's syndrome), the child also has two or more of

the following disturbances:

1. Significant disturbance of social relatedness to parents and peers, with

poor eye contact and a sense of " aloneness. "

2. Repetitive routines such as lining up objects and insisting on the

sameness of certain clothes or certain foods or certain spaces between objects

at the time of eating, etc. These children also may have a fascination with

spinning objects such as wheels of toy cars or records, bizarre attachments to

certain objects such as stripes, pins, pieces of plastic toys.

3. Unusual, inconstant, sensory responsiveness. This can be seen in children

who may appear deaf in one minute and overly sensitive to sound at another.

Another example is a child who often shrinks from a touch but sometimes enjoys

being tickled very forcefully.

4. A child who, in spite of his general level of retardation, has an islet of

special ability at a completely different level that other levels of mental

functioning. These skills may be in music, art, jigsaw puzzles or other visual

spatial skills.

Evaluating autistic features in a Down's syndrome child can be quite difficult.

If the child, for example, appears not to be hearing well, it may not be due to

an autistic feature but may be due to otitis media (middle ear infection) a

common problem seen in Down's syndrome children. A child who is irritable,

withdrawn, with poor eye contact may be a child who is developing a hidden

infection such as in the bladder, the middle ear or other infectious more

commonly seen in a Down's syndrome child. Thus the diagnosis of autistic

features should only be made if it is a consistent pattern over a considerable

period of time where any infectious or other etiologies have carefully ruled

out.

Medical Evaluation

Assuming that the diagnosis has been made of a Down's syndrome child with

autistic features, then a medical evaluation is indicated. The autistic syndrome

is not a single disease but a syndrome of many different etiologies. A

description of a full workup for a child with an autistic syndrome is found in

the book The Biology of The Autistic Syndromes ( and Gillberg, 1985).

This paper is presented to indicate that it is not necessary to immediately move

toward psychotropic drugs in treatment of behavior disorders with Down's

syndrome children. As with any other individual, each child needs to have a

specific clinical evaluation with the type of symptomology studied. For example,

the tendency to place retarded children with poor attention span on stimulant

drugs (pharmacological agents known to make autism worse in some cases) should

be avoided until the child has had an adequate workup. Gladow (1985) discusses

this problem in some detail.

In this paper I am going to give two examples of Down's syndrome children with

autistic features who were found to gave a metabolic disease entity

concomitantly seen in the autistic syndrome. Although, in both cases

identification of the problem appeared to have helped with the management of the

child, it should be noted that single case histories are never conclusive.

However, the problem of identifying enough patients to perform double blind

studies in these rare combination syndromes is a major drawback to scientific

advance in this field.

Purine Abnormalities in Down's Syndrome and the Autistic Syndrome

Elevation of the uric acid both in the blood and in the urine of Down's syndrome

patients has been an area under study for a long time (Pueschel, 1982). There

have been many articles on the subject, a number puzzling over the fact that the

hyperuricenna seen in Down's syndrome is less likely to result in gouty

arthritis than in other individuals. Recently, using recombinant DNA techniques

it has been determined that two of the genes involved in purine biosynthesis,

phosphoribosyl-glycina-mide synthetase (PRGS) and phosphofructokinase (PFKL) are

located on the 21st chromosome ( and Warren, 1985). It is much too early to

know if these genes are the ones responsible for purine over-production in

Down's syndrome, whether there also are modifying genes etc.

Three enzymes — 5-phosphoribosyt-l-pyrophosphate (PRPP synthetase), inosinate

dehydrogenase and adenyl-osuccinate lyase — are enzymes in the purine pathway

known to be abnormal in one of more autistic children. Some of these enzyme

errors have experimental treatments available.

Thus, in evaluating a Down's child with autistic features, a uric acid clearance

may be valuable. Even if it is not possible to pin down the exact gene or enzyme

involved in a child, if the child is a purine overexcretor then dietary measures

reducing purines or allopurinol can be tried in an effort to diminish autistic

features. There are no double blind studies showing that these treatments are of

value. In one 10-year-old boy with Trisomy 21 in my practice, such a diet and

allopurinol appeared to make a difference in the child's attention span and

ability to learn. It may or may not be coincidence that the child's clinical

picture improved on the diet and allopurinol and deteriorated during two

crossover periods off the diet and on placebo.

Lactic Acidosis in Down's Syndrome and the Autistic Syndrome

Lactic acidosis or hyperlactatemia without acidosis in a child indicates some

abnormality in the utilization of sugar, which increases the rate of lactate

production relative to lactate utilization. There is a paper in the literature

describing lactic acidosis in a Down's syndrome child (Hartman et al. 1962). In

my practice, there was a 3-year-old boy with Trisomy 21 who had a very poor

attention span and a number of autistic features. The child was found to have

lactic acidosis on repeated testing. Studies are currently underway in attempts

to find, if possible, which enzyme is involved in the carbohydrate pathway in

this child. Placed on a low carbohydrate diet and thiamin, the child's attention

span and language showed marked improvement, with some evidence of deterioration

or plateauing during two crossover periods. Again, no double blind studies have

been done to confirm these results and, since a specific enzyme has not even

been identified in this child, these results are most preliminary.

Conclusion

Down's syndrome children like other individuals have psychiatric symptoms. They

can appear autistic or become anxious, depressed, anorexic or psychotic (Keegan

et al. 1974; Semansky and Betelman 1984). The solution to helping children lies

in thinking of them as individuals who also happen to have Down's syndrome and

attacking the problem on an individual basis using individual medical therapy as

appropriate. For the Down's syndrome child with autistic features, individual

evaluation is particularly important.

We have the power to enhance the quality of life and the future of Down's

syndrome individuals if we treat them with the care and attention each child

deserves.