Jerome Lejeune

Professor Jérôme Lejeune


One of the greatest humanitarians of the 20th century,
recognized all over the world

Research – Care – Advocacy

Who was Professor Jerome Lejeune?

Biographical Milestones
  • Jérôme Lejeune was born in 1926 in Montrouge, a Parisian suburb.
  • He studied medicine and became a researcher at the CNRS in 1952, eventually becoming an international expert for France on atomic radiation.
  • In July 1958, during a study of chromosomes of a child, he discovered the existence of an extra chromosome on the 21st pair. For the first time ever, a link was established between a state of mental disability and a chromosomal anomaly.
  • In 1962, this extraordinary discovery was greeted with the award of the Kennedy Prize which Jérôme Lejeune received personally from President John F. Kennedy.
  • In 1964, the first chair of fundamental genetics was created for him at the Faculté de Médecine de Paris. While speaking at thousands of conferences around the world, he still maintaining relationships with the children he treated and their families.
  • In 1969, his work on chromosomal pathologies was rewarded with the William Allen Memorial Award.
  • In 1974, he became a member of the Pontifical Academy of Sciences.
  • In 1981 he was elected to the Académie des Sciences Morales et Politiques.
  • In 1983 he joined the Académie Nationale de Médecine. He was an honorary doctor, member or laureate of many other foreign academies, universities and scholarly societies.
  • In 1993 he received the Griffuel Prize for his pioneering work on chromosomal anomalies in cancer.
  • In 1994 he was named president of the Pontifical Academy for life.
  • He died on 3 April 1994, saddened at the thought he had not fulfilled his mission: “I was a physician who should have cured them and I am leaving them. I have the impression I am abandoning them.”
  • In 2007 the case for beatification of Jérôme Lejeune was opened by the Roman Catholic Church.
His Life, His Commitment

A physician by vocation, Jérôme Lejeune was confronted with the struggles experienced by intellectually disabled children and their families at a very early age. Because medicine was powerless to help these children, Jérôme Lejeune decided to dedicate his life to them. He became a researcher with the aim of penetrating the mystery of how this intelligence impairment prevents people from expressing themselves and bringing awareness to the challenges they face.

Discovery of Trisomy 21

In 1958, while working in Prof. Turpin’s laboratory, Dr Jérôme Lejeune discovered the cause of what was then known as mongolism: an extra chromosome in pair 21. On 26 January 1959, the Académie des Sciences published his scientific work (Jérôme Lejeune, Marthe Gautier and Raymond Turpin. Human chromosomes in tissue culture. C. R. Acad. Sciences, 26 January 1959). This condition would henceforth be called trisomy 21.

More History About the Discovery…

For the first time in the world, a link had been established between an intellectual disability and a chromosome abnormality. Parents of children with Down syndrome could now know that their children’ disorder was not hereditary. He later discovered the cause of many other chromosome abnormalities, thereby opening the way to cytogenetics and modern genetics.

Heading the cytogenetics unit at the Hôpital Necker- Enfants Malades in Paris, his consultations became among the most sought after in the world. Helped by his co-workers, he investigated over 30,000 chromosome cases and treated more than 9,000 persons with intelligence disorders.

His utmost concern was to one day succeed in healing the patients who came to see him from around the world. He also fought against the those who wanted to do away with the sick when we are unable to cure them, showing the personhood of his patients with Down syndrome.

A Life Long Commitment

Although the results of his research should have helped medicine to advance towards a cure, they are often used to identify children carrying these diseases as early as possible, usually with the aim of terminating pregnancy.

As soon as the pro-abortion laws were drafted in western countries, Lejeune began advocating for the protection of the unborn with Down syndrome: he gave hundreds of conferences and interviews across the globe in defence of life. In 1974, Pope Paul VI appointed him to the Pontifical Academy of Sciences. In 1981, he was elected to the French Academy of Moral and Political Sciences. In 1994, he became the first Chairman of the Pontifical Academy for Life founded by Pope John-Paul II. He died of cancer on the 3rd of April 1994, Easter morning, thirty-three days after his appointment.

During the World Youth Days in Paris in August 1997, the Pope visited his friend’s grave in Chalô Saint Mars. The cause for the beatification and canonisation of Jérôme Lejeune was opened in Paris on 28 June 2007. The Jérôme Lejeune Foundation was created and state-recognised as a public asset in 1996 in furtherance of Professor Lejeune’s action. It has a triple mission: research, care, and advocacy.

21 Thoughts by Jerome Lejeune

Thought #1: Human genetics can be summarized in this basic creed…

Jerome Lejeune: Servant of God

Before God and men we bear witness that for us every human being is a person.

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