Down's Syndrome is a genetic condition which is the commonest identifiable cause of intellectual disability, accounting for almost one third of cases. It occurs equally in all races with an overall incidence rate of approximately 1 in 800 births.

Conor Ward (Republic of Ireland)

John Langdon Down (1828 - 1896) and Down's Syndrome

The designation Down's syndrome originated in the decision by the Editor of the Lancet in 1961 to opt for this description for the condition previously described as Mongolian Idiocy. A group of 20 of the world's leading geneticists had written suggesting that the condition be known henceforth as Langdon Down Anomaly, Down's Syndrome, or Anomaly or Congenital Acromicria. The designation was confirmed by the World Health Organisation in 1965.

Langdon Down was a brilliant medical student in the London Hospital and after two years as the hospital obstetric resident he was appointed Medical Superintendent of the Royal Earlswood Asylum for Idiots in Redhill, Surrey in 1856.

While in post he also identified other disorders including Prader Willi Syndrome. In 1866 he opened his own private residential centre in Normansfield. This catered for a wide range of intellectual disabilities. His main publication on intellectual disability was in the Lettsomian Lectures which he delivered for the Medical Society of London in 1887.

John Langdon Down was the youngest son of a village grocer in Torpoint in Cornwall. He worked in his father's shop until he was 18 years old. Having first qualified in pharmacy he entered the London Hospital Medical School at the age of 25 where he was a triple gold medallist. Immediately after taking his degree he was appointed Medical Superintendent of the Royal Earlswood Asylum of Idiots. In parallel he was appointed Assistant Physician at the Royal London Hospital.

At Earlswood he was influenced by Dr John Conolly, the reformer of psychiatric hospitals and Official Visitor to Earlswood. Conolly wished to pursue the correlation between the external contours of the skull and specific intellectual and psychological characteristics.

Langdon Down began by examining the palates and tongues of the residents and in his 1862 report he said "in 16 cases the tongue presented a sodden appearance and exhibited transverse furrows on its dorsal surface; in all these patients one is able to trace a marked physiological and psychological agreement. So much do they resemble one another that they might readily be taken for members of the same family. Twelve appear to have very large tongues which in most cases interfered with speech." This was the first indication that he had identified a specific group of patients with unique physical characteristics.

He pursued the project for the identification of skull shapes in several ways. In 1862 and in 1865 he photographed a large number of patients. Over 200 of his black and white negatives have survived. In his definitive publication in what he described the ethnic classification of idiots in 1866, he pointed to the physical features of patients whom he described as Caucasian, Ethiopian, Malayan, American Indian and Mongolian. It was the last of these categories which encompassed the first description of what is now known as Down's syndrome.

He wrote: "It is to this division I wish, in this paper to draw special attention. The very large number of congenital idiots are typical mongols. So marked is this that when placed side by side it is difficult to believe that the specimens compared are not children of the same parents. The number of idiots who have arranged themselves around the Mongolian type is so great and they present such a close resemblance to one another in mental power that I shall describe an idiot member of this racial division selected from the large number who have fallen under my observation.

The face is flat and broad and destitute of prominence. The cheeks are roundish and extended laterally. The eyes are obliquely placed and the internal canthi more than normally distanced from one another. The palpebral fissure is very narrow. The tongue is long, thick and much roughened. The nose is small. The skin has a slight dirty yellowish texture and is deficient in elasticity, giving the impression of being too large for the body." He went on to observe that the co-ordination was poor, the circulation is feeble and there is a tendency to delay in development during the winter, suggesting that in some of his patients there was concurrent thyroid deficiency.

He noted that this group of patients responded very well to training, doing better than would be expected. Their life expectancy however was below average and there was a tendency for the development of tuberculosis.

In 1876 he specifically identified the fold of skin at the inner corner of the eyes which he described as epicanthic folds and he also noted that the ear was usually placed further back in relation to the head and face than in normal children.

It was not until 1959 that Lejeune and colleagues discovered the extra chromosome 21 which was the underlying abnormality in Down's syndrome. Very little new was added to the clinical description of the condition apart from the description of single transverse crease in the palm noted by John Langdon Down's son Reginald in 1908 and the characteristic grey spots on the iris of the eye noted by Brushfield in 1924.

Article published in 2002. Reviewed in 2019; content continues to be relevant.