Former classification of HC
| Classification . | Gene involved and location . | Inheritance . | TSAT . | Other clinical features . |
|---|---|---|---|---|
| Type 1 | HFE; chr. 6 | AR | Increased | Adult-onset; more severe in males; highly variable clinical expression, with predominant liver damage and arthritis |
| Type 2A | HJV (hemojuvelin); chr. 1 | AR | Increased | Earlier onset (eg, <30 y old); similar severity in both sexes; prevalent cardiac and endocrine involvement |
| Type 2B | HAMP (hepcidin); chr. 19 | AR | Increased | Earlier onset (eg, <30 y old); similar severity in both sexes; prevalent cardiac and endocrine involvement |
| Type 3 | TFR2 (transferrin receptor 2); chr. 7 | AR | Increased | Very rare (look for parental consanguinity); clinically similar to type 1, with an earlier onset |
| Type 4A | SLC40A1 (ferroportin); chr. 2 | AD | Low-normal | Adult-onset; IO in the spleen; mild anemia; possible low tolerance to venesection |
| Type 4B | SLC40A1 (ferroportin); chr. 2 | AD | Increased | Very rare; in general, clinically similar to type 1, but more severe/early onset forms are reported |
| Classification . | Gene involved and location . | Inheritance . | TSAT . | Other clinical features . |
|---|---|---|---|---|
| Type 1 | HFE; chr. 6 | AR | Increased | Adult-onset; more severe in males; highly variable clinical expression, with predominant liver damage and arthritis |
| Type 2A | HJV (hemojuvelin); chr. 1 | AR | Increased | Earlier onset (eg, <30 y old); similar severity in both sexes; prevalent cardiac and endocrine involvement |
| Type 2B | HAMP (hepcidin); chr. 19 | AR | Increased | Earlier onset (eg, <30 y old); similar severity in both sexes; prevalent cardiac and endocrine involvement |
| Type 3 | TFR2 (transferrin receptor 2); chr. 7 | AR | Increased | Very rare (look for parental consanguinity); clinically similar to type 1, with an earlier onset |
| Type 4A | SLC40A1 (ferroportin); chr. 2 | AD | Low-normal | Adult-onset; IO in the spleen; mild anemia; possible low tolerance to venesection |
| Type 4B | SLC40A1 (ferroportin); chr. 2 | AD | Increased | Very rare; in general, clinically similar to type 1, but more severe/early onset forms are reported |
AD, autosomal dominant; AR, autosomal recessive; chr., chromosome.