Biographical

Jérôme Lejeune 1927-1994

At the age of 67, Professor Jérôme Lejeune succumbed to cancer, a debilitating disease to which he had devoted part of his research activities.
Jérôme Lejeune grew up as a child in the Paris region. We met in a Paris barracks, on our way to military service in Germany. He had just started «genetics» in Professor Raymond Turpin's team and I had done the same under Professor Maurice Lamy. Despite this rivalry at the top, we always remained, up to the end, the best of friends in the world.
Very early, Jérôme Lejeune was fascinated by the enigma of Down's syndrome. Every possible theory had been put forward to explain such a «condition» : recessive heredity, dominant heredity, chromosomic anomaly. Jérôme Lejeune thought that it could be due to an anomaly similar to Bar's duplication described in the drosophile. Through his work, he encountered Doctor Marthe Gautier who taught him the techniques for cultivating fibroblasts, which she had just acquired in the United States. This collaboration, together with the development of the «first» cytogenetic techniques, led in 1959 to the publication in the Academy of Science Reports of a paper describing the presence in Mongol children of a small supernumerary acrocentric chromosome. This discovery, of what was later to become known as Trisomy 21, was of considerable importance, since it opened the way for the new science of cytogenetics, human first, then animal. Its exponential development in many directions, led to knowledge of the secrets of hereditary science.
Jérôme Lejeune's discoveries in cytogenetics followed on in rapid succession : the description of cat cry syndrome, by deletion of 5p ; the first translocation of the major acrocentrics ; numerous partial aneusomies ; the theory of rings... He put forward the concept of types and countertypes, by which two syndromes, one due to monosomy, and the other due to trisomy, for the same chromosomic segment, are opposed by their clinical signs, for example brachy- versus dolichomesophalangy.
Another contribution was monozygotic heterocaryotic gemellite, characterised by the existence of twins which are «identical» by their blood groups and their immunological tolerance to reciprocal skin grafts, but which differ by a single pair of chromosomes. The first of Jérôme Lejeune's observations concerned twins, one a male, 46, XY and the other suffering from Turner's syndrome, 45, X. This was the result, according to him, of two accidents occurring simultaneously: the formation of monozygotic twins and the formation of a mosaic 46, XY/45, X by loss of the Y in one of the twins. Other observations were published by Jérôme Lejeune, in particular a monozygotic Trisomic 21/Normal couple.
And especially ! Jérôme Lejeune resorted to this form of gemellity to explain the occurrence, during the evolution of species, of an ancestral male/female couple where the individuals bore the same modification: the translocation of chromosome 2, reducing the chromosomic number from N=48 in Pongidae to N=46 in man. This couple could only be Adam and Eve.
In addition to clinical, evolutionary and gemellar cytogenetics, Jérôme Lejeune also contributed to knowledge of cancerous cytogenetics by reporting the first observation of clonal evolution in a Trisomic child suffering from leukaemia. With all the regret which one can imagine, he also realised with hindsight, that on one of his chronic myeloid leukaemia slides , he had a superb Philadelphia «princeps» chromosome which had… escaped him. Even, during the last weeks of his life, aware of his illness, he again devoted his research to finding an explanation for carcinogenesis. With his own doctor, Professor Lucien Israël they sought to correlate cancerogenesis and the evolution of the nervous system in higher organisms. Mere days before the end, Jérôme telephoned me to say that he was struck by the fact that cancer only appears after a certain degree of phylogenetic evolution of living beings, and spares the more primitive species. He asked me whether I had the slightest notion on the subject. I was only able to answer «unfortunately not».
But that is not all of Jérôme Lejeune's creative activity. For a while he was enthusiastic about steric biochemistry. He built molecular models, his «balls», which invaded his laboratory like poppies. His research themes were as diverse as the transmission of nervous current in the synapses or the identification of a «code of congruence» explain the recognition of ADN sequences by protein molecules during genetic or hormonal regulation.
But Jérôme Lejeune's obsession was always to detect the mechanisms of mental deficiency, in order to be able to treat it. And throughout the last years, there was a veritable whirlwind of biochemical flows drawing one another along, like circular gears. His pen sketches were stupefying. His hobbyhorse was the family of folates whose role, in his view, is so fundamental.
Jérôme Lejeune's imaginative expansion was virtually boundless, each day coming up with a new idea, a new concept, a new theory.
As Professor of Fundamental Genetics, Jérôme Lejeune was covered with honours : member of the Institute, member of the Pontifical Academy of Sciences, first president of the Pontifical Academy for Life, member of the Academy of Medicine, doctor honoris causa of numerous foreign universities. He was never awarded the Nobel prize, although his scientific achievements would have more than justified it. And for reasons way beyond purely scientific considerations. They are manifold. They are part of the extra-scientific «environment» of the «erudite» Lejeune. We all know that his moral convictions, proclaimed urbi et orbi, generated both veneration and shame.
I should like to finish by saying quite simply, that for his funeral, the cathedral of Notre Dame de Paris was full, full of people from the world over, a living witness to Jérôme Lejeune's notoriety and universal esteem. I should like to say also, that he left an exemplary wife who remained his unswerving companion from the early days, five children, and twenty-seven grandchildren. Irrefutable proof of his respect for life.