It is expected that at least one third of rare syndromes and disorders are misdiagnosed more than once, or the diagnosis is delayed unnecessarily for a variety of reasons. This book illustrates not only the difficulty experienced to reach a diagnosis of a rare genetic syndrome, but also it demonstrates how experience and mastering the skills of clinically approaching a genetic disorder can change all the assumptions. All the complexities, obscurity, and uncertainty will be transformed to simplicity, and a confident diagnosis will emerge promptly when it comes to the masters of approaches in clinical medicine. All the desperation, inconvenience experienced by the patients and their guardians can be changed to relief , hopes, and certainty when it come to the experts. Wiskott Aldrich syndrome is a rare disorder that has not been described or documented in Iraq. The aim of this book is to describe the first two cases of Wiskott Aldrich syndrome in Iraq.