2025 – PAGE 270 – GENETICS & INHERITED DISEASES

RETT SYNDROME (AKA RETT’S SYNDROME)

Rett syndrome (AKA Rett’s syndrome) results in a regression of developmental milestones and deceleration of growth (look for MICROCEPHALY) after about a year. Patients often have breath-holding spells and seizures. This is an X-linked disorder, but it tends to affect GIRLS more than boys.

MNEMONIC: We REgreX to inform you that your child, REX, is REgreXXing and might be REtarded. PBR’s REgreX for the non-PC mnemonic, but hopefully it helps.

(DOUBLE TAKE) KLINEFELTER SYNDROME (AKA KLINEFELTER’S)

Klinefelter Syndrome (AKA Klinefelter’s) = XXY. It presents with gynecomastia, small testicles, infertility, and normal intelligence to MILD intellectual disability. Patients may have mild motor or speech delay, tall stature with long arms and legs, and a low upper-to-lower segment ratio. For workup, REFER FOR CHROMOSOMAL ANALYSIS!

MNEMONIC: Gynecomastia = Kalvin Klein FELT HER BREASTS. (Yes, I know Kalvin is misspelled > Klinefelter.)

PEARL: Mild intellectual disability may be described as a patient who is “awkward,” “below average in school,” or even just “shy.” Generally, though, these patients have some learning disabilities, but their IQ can be normal.

PEARL: Someone who is tall with long arms and legs could also be described as having a LOW “upper-to-lower segment ratio.”

(DOUBLE TAKE) MARFAN SYNDROME (AKA MARFANS SYNDROME)

Classic features of Marfan Syndrome (AKA Marfans Syndrome) include tall stature with long and thin upper extremities, long fingers, a pectus deformity, joint flexibility/hypermobility, and possible cardiac problems. Cardiac problems may include mitral valve prolapse (MVP), aortic dissection, and mitral or aortic regurgitation. Patients may have a high-arched palate and a speech disorder, but do NOT have cognitive deficits. Patients are also at risk for esophageal perforation.

• PEARLS: Patients can have subluxation of the lens, which may also be seen in Ehlers-Danlos and homocystinuria. If they mention SUPERIOR subluxation of the lens, pick Marfan. Any patient with Marfan should not be cleared for sports participation until they have had an echocardiogram and an evaluation by a cardiologist. If they mention “arm span greater than height,” you’re done.
• IMAGE: www.pbrlinks.com/MARFANS1
• IMAGE: www.pbrlinks.com/MARFANS2
• PEARL: When using your hardcopy book, type the image short links into a browser or use the scrolling edition on your phone or desktop for instant, one-click access to hundreds of high-yield images. It’s fast, saves you from researching images, gives you access to ~400 images, and prevents you from having to carry a 200-page heavier book!
• MNEMONIC: www.pbrlinks.com/MARFANS3 – Michael Phelps won several gold medals. Isn’t that just like winning the Most Valuable Player (MVP = Mitral Valve Prolapse)?