Research IMDSA: Dermatoglyphics in Mosaic Downs

Research: Hopkins-LS Score in Mosaic Downs

Author: Yves Lacassie, M.D., FACMG

Antecedents: The Hopkins Composite Score was a dermatoglyphic index created at Johns Hopkins University by Dr. Digamber Borgaonkar in the late 60’s. Using discriminant functions, the Hopkins composite score was able to separate most of a population of Downs from one of controls. Between 1974 and 1977, Dr. Lacassie modified this system, making it more simple and efficient. It was tested using populations from Louisiana and Santiago, Chile. For this reason, this new version was called Hopkins-LS Score. Using this score, it is possible to diagnose 99% of DS patients using exclusively the dermatoglyphics (study of the ridges and patterns in the palms, fingers and soles). The author has successfully used this system in his practice for 30 years demonstrating it is extremely useful to confirm the diagnosis of Down syndrome, especially in newborns and premature babies. He has also detected a limited number of mosaicisms, which, in agreement with our hypothesis, seem to get intermediate score values. We are progressively increasing the number of mosaic cases, however, a valuable opportunity to study a large number of mosaic patients to confirm or reject our hypothesis will be provided at the conference of the International Mosaic Down Syndrome Association in Richmond, VA, June 29-July 1, 2007. This will be an opportunity to evaluate a larger number of patients with mosaic Down syndrome.

Hypothesis: DSM patients have H-LS scores intermediate between normal controls (negative values) and patients with full trisomy 21 (positive values), depending on the percentage of trisomic cells or level of mosaicism.

Sponsored by International Mosaic Down Syndrome Association

Duration of the Study: 2006-2010