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, myoglobinuria
McArdle disease (skeletal muscle glycogen phosphorylase deficiency)
Infant with hypoglycemia, hepatomegaly
Cori disease (debranching enzyme deficiency) or Von Gierke disease (glucose-6-phsophatase deficiency, more severe)
Myopathy (infantile hypertrophic cardiomyopathy), exercise intolerance
Pompe disease (lysosomal a-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 (glucocerebrosidase deficiency)
Achilles tendon xanthoma
Familial hypercholesterolemia (decreased LDL receptor signaling)