In Reply.—We thank Dr Stephenson for his insightful comments. His observations of sticky saliva in infants with PWS are particularly fascinating and merit especial attention in the prospective studies for which he calls and for which retrospective studies such as ours hope to provide foundation. Similarly, his fine observations of the subtleties of hypotonia in infants with PWS are also most interesting.
"Absence of proof is not proof of absence," and the failure of the majority of examiners to demonstrate brisk deep tendon reflexes in infants with PWS does not absolutely imply that such brisk reflexes can never be elicited. However, we must question the value of a diagnostic sign that is likely to be elicited only by clinical virtuosi; while the brisk tendon reflex may be an excellent diagnostic sign in Dr Stephenson's hands, we think that it is probably of limited value to the average practitioner.
Regarding the penile