Behind the Name

Collaboration of physicians behind first observations of Prader-Willi syndrome

Andrea Prader and Heinrich Willi, along with Alexis Labhart, were responsible for first medical literature on Prader-Willi syndrome.

Andrea Prader and Heinrich Willi, two Swiss pediatricians, and Alexis Labhart, an internist, first described Prader-Labhart-Willi Syndrome in 1956.

Prader was an influential figure in European pediatrics and is considered one of the founding fathers of endocrinology. Willi was a prominent pediatrician and had a notable career in Zurich. Labhart was a Swiss investigator and medical professor born in Russia, who eventually became the head of the metabolic unit and professor of internal medicine at the University of Zurich.

Together, they published the first report on what is known today as Prader-Willi Syndrome. In the report they described children with abnormalities including diminished fetal activity, feeding difficulties in infancy, poor muscle tone, underdeveloped sex organs, short stature, small hands and feet, cognitive impairment and a propensity to develop diabetes in adolescence and adulthood. The report led to further studies in the late 1960s, and many other discoveries about Prader-Willi syndrome.

“We began to realize that there was a group of children with identical symptoms and findings and a typical developmental pattern forming a syndrome which had not been described previously,” Prader said during a speech given at the Prader-Willi Syndrome Association’s 6th National Conference held in Minnesota in 1984.

Prader’s training, career

Prader was born December 23, 1919, in Samedan, Grisons, Switzerland. He studied medicine in Lausanne and Zurich after obtaining his baccalaureat in 1938. After finishing medical school in 1945, he was called to duty at the Swiss Army calvary during World War II. After his postgraduate anatomy training, he specialized in pediatrics. In 1946, Prader married Silvia Schucany and later had two sons and a daughter. He became an assistant to Professor Guido Fanconi at Kinderspital, the Children’s Hospital in Zurich. Prader learned general pediatrics during these early years from Hans Zellweger, the second in the department.

“In 1950, I went to New York to continue my training in Bellevue Hospital under Emmet Holt and to get first hand information about pediatric endocrinology from Lawson Wilkins at Johns Hopkins Hospital in Baltimore,” Prader said. “When I came back to Children’s Hospital in Zurich, Hans Zellweger had left and had become chairman of the Department of Pediatrics at the American University in Beirut.”

In 1951, Prader became chief resident and six years later, he became assistant professor. He succeeded Fanconi as chairman of the department in 1962 and retired from that position in 1986. “My main efforts were to develop pediatric endocrinology and to initiate studies on normal and abnormal growth,” he said.

Prader helped conduct studies that led to the discovery of hereditary fructose intolerance, hypocalcemic pseudo-vitamin D deficiency as a genetic type of rickets, Prader-Willi syndrome and others. His interest turned to adrenal cortex disorders, and his work eventually led to a description of adrenal hyperplasia and the discovery of the 17,20-lyase deficiency. He also made various contributions in the area of growth and puberty, growth hormone and pediatrics as a whole.

He was well-known for his international lectures and was elected a member of the British Royal College of Pediatrics and other societies. He received honorary doctorates and various prizes from several universities and The European Society for Pediatric Endocrinology created an annual award, The Andrea Prader Prize, for Prader which is given to a member who demonstrates leadership and accomplishment in the field of pediatric endocrinology.

Prader died on June 3, 2001 at the age of 81.

Willi’s education, accomplishments

Heinrich Willi was born the sixth of nine children on March 4, 1900 in Chur, Switzerland. He attended the University of Zurich, and in 1925, became a resident at both the Zurich Institute of Pathological Anatomy and the Winterthur Hospital department of medicine.

Three years later, he went to the Children’s Hospital in Zurich, trained under Fanconi and became assistant medical director in 1930. Six years later, he obtained his doctorate with a thesis on childhood leukemias; a year later, he was named successor to Professor Bernheim-Karrer, the first practicing pediatrician in Zurich, and director of the University Hospital of Neonatology. Willi remained director of neonatology until he retired in 1970.

Willi was interested in medical research and studied topics including dietary experiments, the hematological effects of ascariasis and the delineation of the leukemias of childhood. He was one of the first to recognize bone marrow aspiration as a technique for investigation. Later in his career, he investigated neonatal pathology and developmental abnormalities in infants born to mothers with diabetes.

Willi was elected president of the Swiss Association for Pediatrics from 1959 to 1962 and was nominated for the German Scientific Society, Leopoldina. He managed a large, private practice and did so up until his death on February 16, 1971, at the age of 71.


Dr. Vanja Holm (front) the first physician to be involved with Prader-Willi syndrome in the United States. Front: Dr. Vanja Holm. In back left to right: Dr. Hans Zellweger, Dr. Gene Deterling and his wife Fausta (founded of the Prader-Willi Syndrome Association-USA), Dr. Andrea Prader and Dr. Sam Beltram, the first Prader-Willi Syndrome Association (USA) president. Taken at the national conference in 1984.

Source: Prader-Willi Syndrome Association (USA)

A collaboration for advancement

“Our [Prader and Labhart] first patient, Albert, had been seen as a newborn by Heinrich Willi, later by us in the Children’s Hospital and when he was an adolescent and a young adult by Alex Labhart,” Prader said. “In many discussions with Heinrich Willi, we recalled other obese and mentally retarded patients who because of severe hypotonia had been in the newborn nursery for prolonged periods.”

In the next few years, their paper was presented at conferences including the 8th International Congress of Pediatrics in Copenhagen and the Swiss Society of Endocrinology, according to Prader. It was published in the Swiss Journal of Medicine.

“At first our paper did not stimulate interest in the medical profession,” Prader said. In 1961, Prader and Willi reported on the syndrome at the 2nd International Congress of Mental Retardation in Vienna, Austria. Within the next few years, observations and publication appeared in the United States, the United Kingdom and France, which were followed by reports from most western countries and Japan, according to Prader.

Together, Prader, Labhart and Willi published the first paper on what has come to be known as Prader-Willi syndrome and helped pave the way to the progress seen today.

Research into the syndrome during the past decade has begun to establish links between genetic abnormalities, brain function and behavioral and cognitive attributes, according to an article in the Journal of the Academy of Child & Adolescent Psychiatry. – by Christen Haigh

For more information:
  • Beighton P, Beighton G. The Person Behind the Syndrome. New York: Springer Verlag;1997:194-195, 214.
  • Couper RTL, Couper JJ. Prader-Willi syndrome. Lancet. 2000;356:673-675.
  • Heinemann J. Farewell to two heroes. The Gathered View. 2001;July-August:6-7,11.
  • Foundation for Prader-Willi Research website. www.fpwr.org. Accessed July 31, 2008.
  • Prader-Willi Syndrome Association website. www.pwsausa.org. Accessed April 29, 2008.
  • State MW, Dykens EM. Genetics of childhood disorders: Prader-Willi syndrome: genes, brain and behavior. J Am Acad Child Adolesc Psychiatry. 2000;39:797-800.
  • Zachman M. Andrea Prader 1919-2001. Horm Res. 2001;doi:10.1159/000048118.

Andrea Prader and Heinrich Willi, two Swiss pediatricians, and Alexis Labhart, an internist, first described Prader-Labhart-Willi Syndrome in 1956.

Prader was an influential figure in European pediatrics and is considered one of the founding fathers of endocrinology. Willi was a prominent pediatrician and had a notable career in Zurich. Labhart was a Swiss investigator and medical professor born in Russia, who eventually became the head of the metabolic unit and professor of internal medicine at the University of Zurich.

Together, they published the first report on what is known today as Prader-Willi Syndrome. In the report they described children with abnormalities including diminished fetal activity, feeding difficulties in infancy, poor muscle tone, underdeveloped sex organs, short stature, small hands and feet, cognitive impairment and a propensity to develop diabetes in adolescence and adulthood. The report led to further studies in the late 1960s, and many other discoveries about Prader-Willi syndrome.

“We began to realize that there was a group of children with identical symptoms and findings and a typical developmental pattern forming a syndrome which had not been described previously,” Prader said during a speech given at the Prader-Willi Syndrome Association’s 6th National Conference held in Minnesota in 1984.

Prader’s training, career

Prader was born December 23, 1919, in Samedan, Grisons, Switzerland. He studied medicine in Lausanne and Zurich after obtaining his baccalaureat in 1938. After finishing medical school in 1945, he was called to duty at the Swiss Army calvary during World War II. After his postgraduate anatomy training, he specialized in pediatrics. In 1946, Prader married Silvia Schucany and later had two sons and a daughter. He became an assistant to Professor Guido Fanconi at Kinderspital, the Children’s Hospital in Zurich. Prader learned general pediatrics during these early years from Hans Zellweger, the second in the department.

“In 1950, I went to New York to continue my training in Bellevue Hospital under Emmet Holt and to get first hand information about pediatric endocrinology from Lawson Wilkins at Johns Hopkins Hospital in Baltimore,” Prader said. “When I came back to Children’s Hospital in Zurich, Hans Zellweger had left and had become chairman of the Department of Pediatrics at the American University in Beirut.”

In 1951, Prader became chief resident and six years later, he became assistant professor. He succeeded Fanconi as chairman of the department in 1962 and retired from that position in 1986. “My main efforts were to develop pediatric endocrinology and to initiate studies on normal and abnormal growth,” he said.

Prader helped conduct studies that led to the discovery of hereditary fructose intolerance, hypocalcemic pseudo-vitamin D deficiency as a genetic type of rickets, Prader-Willi syndrome and others. His interest turned to adrenal cortex disorders, and his work eventually led to a description of adrenal hyperplasia and the discovery of the 17,20-lyase deficiency. He also made various contributions in the area of growth and puberty, growth hormone and pediatrics as a whole.

He was well-known for his international lectures and was elected a member of the British Royal College of Pediatrics and other societies. He received honorary doctorates and various prizes from several universities and The European Society for Pediatric Endocrinology created an annual award, The Andrea Prader Prize, for Prader which is given to a member who demonstrates leadership and accomplishment in the field of pediatric endocrinology.

Prader died on June 3, 2001 at the age of 81.

Willi’s education, accomplishments

Heinrich Willi was born the sixth of nine children on March 4, 1900 in Chur, Switzerland. He attended the University of Zurich, and in 1925, became a resident at both the Zurich Institute of Pathological Anatomy and the Winterthur Hospital department of medicine.

Three years later, he went to the Children’s Hospital in Zurich, trained under Fanconi and became assistant medical director in 1930. Six years later, he obtained his doctorate with a thesis on childhood leukemias; a year later, he was named successor to Professor Bernheim-Karrer, the first practicing pediatrician in Zurich, and director of the University Hospital of Neonatology. Willi remained director of neonatology until he retired in 1970.

Willi was interested in medical research and studied topics including dietary experiments, the hematological effects of ascariasis and the delineation of the leukemias of childhood. He was one of the first to recognize bone marrow aspiration as a technique for investigation. Later in his career, he investigated neonatal pathology and developmental abnormalities in infants born to mothers with diabetes.

Willi was elected president of the Swiss Association for Pediatrics from 1959 to 1962 and was nominated for the German Scientific Society, Leopoldina. He managed a large, private practice and did so up until his death on February 16, 1971, at the age of 71.


Dr. Vanja Holm (front) the first physician to be involved with Prader-Willi syndrome in the United States. Front: Dr. Vanja Holm. In back left to right: Dr. Hans Zellweger, Dr. Gene Deterling and his wife Fausta (founded of the Prader-Willi Syndrome Association-USA), Dr. Andrea Prader and Dr. Sam Beltram, the first Prader-Willi Syndrome Association (USA) president. Taken at the national conference in 1984.

Source: Prader-Willi Syndrome Association (USA)

A collaboration for advancement

“Our [Prader and Labhart] first patient, Albert, had been seen as a newborn by Heinrich Willi, later by us in the Children’s Hospital and when he was an adolescent and a young adult by Alex Labhart,” Prader said. “In many discussions with Heinrich Willi, we recalled other obese and mentally retarded patients who because of severe hypotonia had been in the newborn nursery for prolonged periods.”

In the next few years, their paper was presented at conferences including the 8th International Congress of Pediatrics in Copenhagen and the Swiss Society of Endocrinology, according to Prader. It was published in the Swiss Journal of Medicine.

“At first our paper did not stimulate interest in the medical profession,” Prader said. In 1961, Prader and Willi reported on the syndrome at the 2nd International Congress of Mental Retardation in Vienna, Austria. Within the next few years, observations and publication appeared in the United States, the United Kingdom and France, which were followed by reports from most western countries and Japan, according to Prader.

Together, Prader, Labhart and Willi published the first paper on what has come to be known as Prader-Willi syndrome and helped pave the way to the progress seen today.

Research into the syndrome during the past decade has begun to establish links between genetic abnormalities, brain function and behavioral and cognitive attributes, according to an article in the Journal of the Academy of Child & Adolescent Psychiatry. – by Christen Haigh

For more information:
  • Beighton P, Beighton G. The Person Behind the Syndrome. New York: Springer Verlag;1997:194-195, 214.
  • Couper RTL, Couper JJ. Prader-Willi syndrome. Lancet. 2000;356:673-675.
  • Heinemann J. Farewell to two heroes. The Gathered View. 2001;July-August:6-7,11.
  • Foundation for Prader-Willi Research website. www.fpwr.org. Accessed July 31, 2008.
  • Prader-Willi Syndrome Association website. www.pwsausa.org. Accessed April 29, 2008.
  • State MW, Dykens EM. Genetics of childhood disorders: Prader-Willi syndrome: genes, brain and behavior. J Am Acad Child Adolesc Psychiatry. 2000;39:797-800.
  • Zachman M. Andrea Prader 1919-2001. Horm Res. 2001;doi:10.1159/000048118.

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