Type 2A is caused by inheriting two mutated alleles, one from each parent, for the HJV (aka HFE2) gene, which encodes the protein hemojuvelin. Hemojuvelin is responsible for the maintaining correct levels of the protein hepcidin, which regulates iron absorption in the blood. Without functional hemojuvelin, hepcidin levels are reduced, and the amount of iron absorbed into the blood during digestion is unable to be halted. Type 2B is caused by inheriting two mutated alleles, one from each parent, for the HAMP gene, which encodes the protein hepcidin. Hepcidin is responsible for regulating absorption of iron from the small intestine to the blood during the digestion of food, such to prevent blood iron levels from becoming too high. A lack of functional hepcidin prevents the body from stopping iron absorption when it has already reached adequate levels.Type 2A is the most common form, accounting for roughly 9 out of every 10 cases of the disease. Diagnosis
An individual may be suspected to have this condition based on their medical history, physical exam findings, and blood tests, and confirmation of the diagnosis can be made with further testing, often with use of gene panels. Differential Diagnosis
Juvenile hemochromatosis shares signs and symptoms with many other conditions including:
Other types of hereditary hemochromatosis
Atransferrinemia
Aceruloplasminemia
African iron overload
Neonatal hemochromatosis
Transfusional iron overload and other forms of secondary hemochromatosis
Porphyria cutanea tarda

Blood Testing
The presence of hemochromatosis may be discovered incidentally on blood testing, or a diagnosis suspected based on symptoms may be supported or ruled out by blood testing.
Ethylmalonic encephalopathy (EE) is a rare autosomal recessive inborn error of metabolism. Patients affected with EE are typically identified shortly after birth, with symptoms including diarrhea, petechiae and seizures. The genetic defect in EE is thought to involve an impairment in the degradation of sulfide intermediates in the body. Hydrogen sulfide then builds up to toxic levels. EE was initially described in 1994. Most cases of EE have been described in individuals of Mediterranean or Arabic origin. Signs and symptoms
Neurologic signs and symptoms include progressively delayed development, weak muscle tone (hypotonia), seizures, and abnormal movements. The bodys network of blood vessels is also affected. Children with this disorder may experience rashes of tiny red spots (petechiae) caused by bleeding under the skin and blue discoloration in the hands and feet due to reduced oxygen in the blood (acrocyanosis). Chronic diarrhea is another common feature of ethylmalonic encephalopathy. EE is often identified by urine organic acid analysis, the excretion of ethylmalonic acid, methylsuccinic acid, isobutyrylglycine and isovalerylglucine. Patients will also often have elevated thiosulphate concentration in their urine.The signs and symptoms of ethylmalonic encephalopathy are apparent at birth or begin in the first few months of life. Problems with the nervous system typically worsen over time, and most affected individuals survive only into early childhood. A few children with a milder, chronic form of this disorder have been reported, and there can be considerable phenotypic variation, even within families. The life expectancy of individuals with EE is less than ten years.