Lysinuric protein intolerance (LPI) typically presents after an infant is weaned from breast milk or formula; variable findings include recurrent vomiting and episodes of diarrhea, episodes of stupor and coma after a protein-rich meal, poor feeding, aversion to protein-rich food, failure to thrive, hepatosplenomegaly, and muscular hypotonia. Over time, findings include: poor growth, osteoporosis, involvement of the lungs (progressive interstitial changes, pulmonary alveolar proteinosis) and of the kidneys (progressive glomerular and proximal tubular disease), hematologic abnormalities (normochromic or hypochromic anemia, leukopenia, thrombocytopenia, erythroblastophagocytosis in the bone marrow aspirate), and a clinical presentation resembling the hemophagocytic lymphohistiocytosis/macrophagic activation syndrome. Hypercholesterolemia, hypertriglyceridemia, and acute pancreatitis can also be seen.

Goodpasture syndrome, also known as anti-GBM disease, is a rare autoimmune disease consisting of alveolar hemorrhage and glomerulonephritis secondary to circulating antiglomerular basement membrane (anti-GBM) antibodies. Anti-GBM antibodies are directed against an antigen intrinsic to the alpha-3 chain of type IV collagen (COL4A3; 120070) that is expressed in the GBMs of the glomerular capillary loops and the basal membrane of the pulmonary alveoli. Goodpasture syndrome is suspected in patients with hemoptysis and hematuria and is confirmed by the presence of anti-GBM antibodies in renal biopsy specimens and serum. Patients with human leukocyte antigen HLA-DR15 and HLA-DR4 are susceptible to the development of Goodpasture syndrome. Reported cases of familial Goodpasture syndrome are extremely rare (summary by Angioi et al., 2017).

An extremely rare form of carbohydrate deficient glycoprotein syndrome characterized clinically in the single reported case by repeated hemorrhagic incidents, including severe pulmonary hemorrhage.

Hereditary hemorrhagic telangiectasia (HHT) is characterized by the presence of multiple arteriovenous malformations (AVMs) that lack intervening capillaries and result in direct connections between arteries and veins. The most common clinical manifestation is spontaneous and recurrent nosebleeds (epistaxis) beginning on average at age 12 years. Telangiectases (small AVMs) are characteristically found on the lips, tongue, buccal and gastrointestinal (GI) mucosa, face, and fingers. The appearance of telangiectases is generally later than epistaxis but may be during childhood. Large AVMs occur most often in the lungs, liver, or brain; complications from bleeding or shunting may be sudden and catastrophic. A minority of individuals with HHT have GI bleeding, which is rarely seen before age 50 years.

Autoimmune interstitial lung, joint, and kidney disease is an autosomal dominant systemic autoimmune disorder characterized by interstitial lung disease, inflammatory arthritis, and immune complex-mediated renal disease. Laboratory studies show high-titer autoantibodies. Symptoms appear in the first 2 decades of life, but there is incomplete penetrance (summary by Watkin et al., 2015).

Immunodeficiency-91 and hyperinflammation (IMD91) is an autosomal recessive complex immunologic disorder characterized by both immunodeficiency and recurrent infections, often to viruses or mycobacteria, as well as by hyperinflammation with systemic involvement. Affected individuals present in infancy with variable features, including fever, infection, thrombocytopenia, renal or hepatic dysfunction, recurrent infections, or seizures. Most patients eventually develop hepatic or renal failure, compromised neurologic function, lymphadenopathy or hepatosplenomegaly, and multiorgan failure resulting in death. More variable features may include intermittent monocytosis, features of hemophagocytic lymphohistiocytosis (HLH), and serologic evidence of hyperinflammation. The disorder is thought to result from dysregulation of the interferon response to viral stimulation in the innate immune system (summary by Le Voyer et al., 2021; Vavassori et al., 2021).