A 12-year-old healthy Jewish girl is found on routine blood count to have a mild anemia, leukopenia, and thrombocytopenia. Physical examination reveals an enlarged spleen. An x-ray of the femur is described as “appearing to be an Erlenmeyer flask.” Bone marrow examination shows abnormal cells. The diagnosis can be confirmed by measurement of activity of which of the following?
a. Sphingomyelinase activity
b. Hexosamidase A
c. Sulfatase A
e. Ceramide trihexosidase
the answer is below…
The United States Medical Licensing Examination, or USMLE for short, is a three-part licensing examination that is required in order to receive a license to practice medicine within the United States.
The USMLE assesses a physician’s ability to apply knowledge, concepts, and principles, and to determine fundamental patient-centered skills that are important in health and disease and that constitute the basis of safe and effective patient care.Examination committees composed of medical educators and clinicians from across the United States and its territories prepare the examination materials each year.
This exam is designed by the Federation of State Medical Boards and the National Board of Medical Examiners to determine whether or not an individual understands and can apply the knowledge necessary to practice medicine safely and intelligently.
The USMLE is actually comprised of three different exams that are referred to as steps, which examine the individual’s knowledge of specific topics related to the field of medicine such as basic science, medical knowledge, medical skills, clinical science, and the application of all of these skills and areas of knowledge in the medical field.
All three steps of the USMLE include a series of computerized multiple-choice questions, but the format of the exam and the information covered in each multiple-choice section is different for each step of the USMLE. The USMLE Step II also has a clinical skills portion that examines an individual’s ability to work with real patients and the USMLE Step III has a computerized patient simulation portion in addition to the multiple-choice section of the exam. In order for an individual to receive a license to practice medicine, the individual must pass all three steps of the USMLE.
The answer is d; Glucocerebrosidase.[4-6]
Gaucher disease is characterized by a glucocerebrosidase deficiency, which causes an abnormal accumulation of glucocerebroside in the reticuloendothelial system. Bone marrow aspirate shows the typical Gaucher cells engorged with glucocerebroside. Replacement of marrow with these cells leads to anemia, leukopenia, and thrombocytopenia. The liver and spleen can also be involved. Serum acid phosphatase is elevated. X-ray demonstrates an Erlenmeyer-flask appearance of the long bones. The diagnosis of Gaucher disease is confirmed by the absence of glucocerebrosidase activity in leukocytes, in cultured skin fibroblasts, and in liver cells. Prenatal diagnosis by enzyme analysis is now possible. In the most common form of Gaucher disease, adult type I, there is no involvement of the central nervous system. Therefore, MRI of the brain is not indicated.
Sphingomyelinase deficiency causes type A Niemann-Pick disease; hexosaminidase A deficiency causes Sandhoff disease; sulfatase A deficiency causes juvenile metachromatic leukodystrophy; and serum trihexosidase causes Fabry disease.