Classic Presentations

• Gout, intellectual disability, self-mutilating behavior in a boy

  Lesch-Nyhan syndrome (HGPRT deficiency, X-linked recessive)
• Situs inversus, chronic sinusitis, bronchiectasis, infertility

  Kartagener syndrome (dynein arm defect affecting cilia)
• Blue sclera

  Osteogenesis imperfecta (type I collagen defect)
• Elastic skin, hypermobility of joints, increased bleeding tendency

  Ehlers-Danlos syndrome (type V collagen defect, type III collagen defect seen in vascular subtype)
• Arachnodactyly, lens dislocation (upward), aortic dissection, hyperflexible joints


  Marfan syndrome (fibrillin defect)
• Calf pseudohypertrophy


  Muscular dystrophy (most commonly Duchenne, due to X-linked recessive frameshift mutation of dystrophin gene)
• Child uses arms to stand up from squat

  Duchenne muscular dystrophy (Gowers sign)
• Slow, progressive muscle weakness in boys

  Becker muscular dystrophy (X-linked non-frameshift deletions in dystrophin; less severe than Duchenne)
• Infant with cleft lip/palate, microcephaly or holoprosencephaly, polydactyly, cutis aplasia

  Patau syndrome (trisomy 13)
• Infant with microcephaly, rocker-bottom feet, clenched hands, and structural heart defect

  Edward syndrome (trisomy 18)
• Single palmar crease

  Down syndrome
• Dilated cardiomyopathy, edema, alcoholism, or malnutrition

  Wet beriberi (thiamine [vitamin B1] deficiency)
• Dermatitis, dementia, diarrhea

  Pellagra (niacin [vitamin B3] deficiency)
• Swollen gums, mucosal bleeding, poor wound healing, petechiae

  Scurvy (vitamin C deficiency: can't hydroxylate proline/lysine for collagen synthesis)
• Chronic exercise intolerance with myalgia, fatigue, painful cramps, myoblobinuria

  McArdle disease (skeletal muscle glycogen phosphorylase deficiency)
• Infant with hypoglycemia, hepatomegaly

  Cori disease (debranching enzyme deficiency) or Von Gierke disease (glucose-6-phosphate deficiency, more severe)
• Myopathy (infantile hypertrophic cardiomyopathy), exercise intolerance

  Pompe disease (lysosomal alpha-1,4-glucosidase deficiency)
• "Cherry-red spots" on macula

  Tay-Sachs (ganglioside accumulation) or Neimann-Pick (sphingomyelin accumulation), central retinal artery occlusion
• Hepatosplenomegaly, pancytopenia, osteoporosis, avascular necrosis of femoral head, bone crises

  Gaucher disease (beta-glucocerebrosidase deficiency)
• Achilles tendon xanthoma

  Familial hypercholesterolemia (decreased LDL receptor signaling)
• Anaphylaxis following blood transfusion

  IgA deficiency
• Male child, recurrent infections, no mature B cells

  X-linked agammaglobulinemia (Bruton tyrosine kinase)
• Recurrent cold (noninflamed) abscesses, eczema, high serum IgE, increased eosinophils

  Hyper-IgE syndrome (Job syndrome: neutrophil chemotaxis abnormality)
• "Strawberry tongue"

  Scarlet fever or Kawasaki disease
• Abdominal pain, diarrhea, leukocytosis, recent antibiotic use

  Clostridium difficile infection
• Back pain, fever, night sweats

  Pott disease (vertebral TB)
• Adrenal hemorrhage, hypotension, DIC

  Waterhouse-Friderichsen syndrome (meningococcemia)
• Red "currant jelly" sputum in alcoholic or diabetic patients

  Klebsiella pneumoniae pneumonia
• Large rash with bull's-eye appearance

  Erythema migrans from Ixodes tick bite (Lyme disease: Borrelia)
• Ulcerated genital lesion

  Nonpainful, indurated: chancre (primary syphilis, Treponema pallidum)

  Painful, with exudate: chancroid (Haemophilus ducreyi)
• Pupil accommodates but doesn't react

  Neurosyphilis (Argyll Robertson pupil)
• Smooth, moist, painless, wart-like lesion on genitals

  Condylomata lata (secondary syphilis)
• Rash on palms and soles

  Coxsackie A, secondary syphilis, Rocky Mountain spotted fever
• Black eschar on face of patient with diabetic keotacidosis

  Mucor or Rhizopus fungal infection
• Chorioretinitis, hydrocephalus, intracranial calcifications

  Congenital toxoplasmosis
• Child with fever later develops red rash on face that spreads to body

  Erythema infectiosum/fifth disease ("slapped cheeks" appearance, caused by parvovirus B19)
• Fever, cough, conjunctivitis, coryza, diffuse rash

  Measles
• Small, irregular red spots on buccal/lingual mucosa with blue-white centers

  Koplik spots (measles [rubeola] virus)
• Bounding pulses, wide pulse pressure, diastolic heart murmur, head bobbing

  Aortic regurgitation
• Systolic ejection murmur (crescendo-decrescendo)

  Aortic stenosis