Supplementary Material for: Co-Occurring Atypical Galactosemia and Wilson Disease

<b><i>Introduction:</i></b> Classic galactosemia is a disorder of the galactose metabolism and is inherited as an autosomal recessive disease. It is caused by a complete or severe deficiency of galactose-1-phosphate uridyltransferase (GALT), and in rare cases, atypical galactosemia can manifest at older ages. Wilson disease (WD) is a disorder of the copper metabolism that, like galactosemia, is inherited as an autosomal recessive disease. Hepatic, neurological, or psychiatric symptoms can be seen, independently or in combination, and symptoms vary from family to family. We present here a patient diagnosed with both WD and galactosemia. <b><i>Case Presentation:</i></b> A 6-year-old girl was referred to our center with elevated transaminase levels and hepatosplenomegaly. The child, birthweight of 2,200 g, was born to first-degree consanguineous parents after a full-term uneventful pregnancy and was hospitalized in the neonatal period due to indirect hyperbilirubinemia, gastrointestinal bleeding, diarrhea lasting 2 weeks, and elevated liver enzymes. Hepatosplenomegaly was evident at the time of admission, a cataract was detected, and a neuropsychiatric evaluation revealed borderline mental capacity, as well as cognitive and speech retardation. Metabolic investigations revealed no specific findings other than trace positivity of reducing substances in the urine. A liver biopsy revealed copper accumulation in hepatocytes and low ceruloplasmin levels. Although WD was suspected in the patient, this diagnosis did not explain the intellectual disability, behavioral disorder, or cataract findings. A genetic analysis revealed homozygous mutations in the <i>ATP7B</i> and <i>GALT</i> genes. The galactose-1-phosphate uridyltransferase enzyme level was found to be low, and the patient was diagnosed with coexisting WD and galactosemia. <b><i>Conclusion:</i></b> Coexistences of rare genetically transmitted diseases can be seen in countries where consanguineous marriages are common (Saudi Arabia, Iran, Pakistan, etc.), as in our country, Turkey.