WBR0315
| Author | [[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1] (Reviewed by Yazan Daaboul, M.D.)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Reproductive |
| Prompt | [[Prompt::A 15-year-old girl is brought by her parents to the physician’s office for a routine check-up. The patient's past medical history is remarkable for congenital hip dislocation. The patient appears short with low-set ears, a webbed neck with redundant neck folds, and a broad-shield chest. Physical examination is remarkable for delayed femoral pulses. Which of the following conditions is associated with this patient's disease?]] |
| Answer A | AnswerA::"3" sign on chest x-ray in the left upper mediastinal shadow |
| Answer A Explanation | AnswerAExp::"3" sign on chest x-xray in the left upper mediastinal shadow is characteristic of post-ductal coarctation of the aorta. In contrast, patients with Turner syndrome typically have a pre-ductal coarctation of the aorta. |
| Answer B | AnswerB::Early-onset accumulation of β-amyloid deposits in the brain |
| Answer B Explanation | [[AnswerBExp::Down syndrome is associated with early-onset Alzheimer's disease due to early accumulation of beta-amyloid deposits in the brain]] |
| Answer C | AnswerC::Fused kidney low in the abdomen under the inferior mesenteric artery |
| Answer C Explanation | AnswerCExp::Turner syndrome is associated with horseshoe kidney, a renal fusion anomaly that leads to trapping of the fused kidney low in the abdomen under the inferior mesenteric artery. |
| Answer D | AnswerD::Sustained contraction of the thenar eminenence when tapping with a reflex hammer |
| Answer D Explanation | AnswerDExp::Percussion myotonia is a sustained contraction of the thenar eminence when tapping with a reflex hammer. It is characteristic of myotonic dystophy. |
| Answer E | AnswerE::Mirror image reversal of major visceral organs |
| Answer E Explanation | [[AnswerEExp::Situs inversus is a congenital condition that results in the mirror image reversal of major visceral organs. Kartagener syndrome, which is caused by microtubulular dynein arm defect, is associated with situs inversus, infertility, recurrent sinusitis, and bronchiectasis.]] |
| Right Answer | RightAnswer::C |
| Explanation | [[Explanation::Turner syndrome is caused by the a complete or partial loss of one copy of the X chromosome, an abnormal structure of the X chromosome, or mosaicim of a 45,XO cell line with another cell line. The karyotype of patients with Turner syndrome is 45,XO. Turner syndrome affects 1/2000 to 1/3000 live-born girls. It has a variable phenotypic expression, but some features are common.
Facial characteristics include abnormalities caused by lymphatic obstruction, such redundant neck folds, low posterior hairlines, and neck webbing (pterygium colli). Other signs of obstructive lymphedema include cystic hygroma, acral congenital lymphedema, and interstitial congestion. Also, patients have posteriorly rotated ears, downward slanting of the eyes, and epicanthal folds. Skeletal features include short stature, congenital hip dislocation, scoliosis, broad shield-shaped chest with a square torso and widely spaced nipples, and cubitus valgus (increased carrying angle of the elbow). Patients often also have dental crowding, micrognathia or prognathia, and a posterior rotation of the mandible. Females with Turner syndrome typically experience gonadal dysgenesis (or less commonly agenesis), which results in amenorrhea, infertility, and the presence of a hypoplastic uterus due to low estrogen levels. Consequently, the loss of negative feedback inhibition results in elevated FSH and LH levels. Turner syndrome is also associated with cardiac abnormalities such as pre-ductal coarctation of the aorta (delayed femoral pulses), and bicuspid aortic valve. Turner syndrome is also associated with the presence of a horseshoe kidney, a renal fusion anomaly that leads to trapping of the fused kidney low in the abdomen under the inferior mesenteric artery. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Delayed femoral pulses, WBRKeyword::Reproductive, WBRKeyword::Chromosome, WBRKeyword::Karyotype, WBRKeyword::Turner syndrome, WBRKeyword::Ovulation, WBRKeyword::Genetics, WBRKeyword::Turner's syndrome, WBRKeyword::Horseshoe kidney, WBRKeyword::Lymphedema, WBRKeyword::Webbed neck, WBRKeyword::Short stature |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |