2025 – PAGE 256 – GENETICS & INHERITED DISEASES

PEUTZ-JEGHERS SYNDROME (AKA HEREDITARY INTESTINAL POLYPOSIS)

Criteria for Peutz-Jeghers syndrome (AKA hereditary intestinal polyposis) include family history, hamartomatous GI polyps, and benign, hyperpigmented macules on the lips or oral mucosa. This condition is diagnosed by noting two out of three criteria. Polyps can lead to obstruction or intussusception, so they should be removed. The lifetime risk of multiple types of cancer is increased, so frequent screenings are done (pap smears, colonoscopy, testicular exam, etc.).

IMAGE: www.pbrlinks.com/PEUTZJEGHERS1
IMAGE: www.pbrlinks.com/PEUTZJEGHERS2
IMAGE: www.pbrlinks.com/PEUTZJEGHERS3

GARDNER SYNDROME (AKA GARDNER’S SYNDROME)

Garner syndrome is a subtype of familial adenomatous polyposis. The primary findings for Gardner syndrome (AKA Gardner’s syndrome) are the premalignant polyps throughout the intestines. Other findings include supernumerary teeth (extra teeth) and tumors in other parts of the body (especially benign bone tumors, called osteomas).

MNEMONIC: Imagine a psychotic MEXICAN GARDENER using a MACHETE to harvest COLONIC POLYPS that look like red onions from the GARDEN of death, along with BONES and TEETH. (The MACHETE represents the need for surgical resection of premalignant polyps.)

(DOUBLE TAKE) RETINOBLASTOMA

The primary finding for retinoblastoma is LEUKOCORIA. There is increased risk of osteogenic sarcoma (AKA osteosarcoma) of a long bone in the future. The inheritance pattern is actually a little confusing, with there being a strong genetic component but also a high rate of spontaneous mutations.

PEARLS: Avoid completely discounting this disorder just because there is no family history. Retinoblastoma is a prime example of a disorder that often occurs due to spontaneous mutations. If you are given information about chromosome 13 and an eye problem, or if you are given the X-ray of a long bone (such as a femur, tibia, humerus, radius, or ulna), consider this diagnosis.

IMAGE: www.pbrlinks.com/RETINOBLASTOMA1

MNEMONIC: “BLAST” from the introductory mnemonic.

MNEMONIC: RAT-inoblastoma. Imagine having a birthday cake made in the shape of your dad wearing a tuxedo. You go into the kitchen to get it, and you find two WHITE RATs gnawing at the cake. One is nibbling on the right EYE (retinoblastoma), and the other is nibbling at the TIBIA (a long bone). Just as you get close, the tibia breaks and the entire thing collapses!

REMINDER: Leukocoria with loss of the red light reflex is seen in retinoblastoma as well as cataracts.

OTHER AUTOSOMAL DOMINANT DISORDERS

• von Willebrand Factor Deficiency (AKA vWF Deficiency): See Hematology.
• HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY (HOCM): An autosomal dominant disorder like Noonan! See Cardiology.
• ACUTE INTERMITTENT PORPHYRIA(AIP): A disorder of heme synthesis that causes symptoms when there is accumulation of a metabolite in the cytoplasm. Symptoms may include abdominal pain, confusion, weakness, and headaches. Triggers may include infection, low carbohydrate intake, and certain medications (seizure and sulfa medications). Treat with a D10 infusion and stop any offending agents.
• RETINITIS PIGMENTOSA: Retinitis pigmentosais a retinal dystrophy that eventually leads to blindness.

PEARL: There are multiple inheritance patterns (autosomal dominant, autosomal recessive, X-linked) so you will not be asked to identify a single inheritance pattern, BUT look for a family history.

MNEMONIC: PIG-men-tuXa. Or, imagine a blind, PIG-like MAN wearing sunglasses, a tuX and using a walking stick.