<unk> , is an autosomal recessive metabolic disorder marked by an accumulation of galactose and galactitol secondary to the decreased conversion of galactose to galactose-1-phosphate by<unk> . The disorder is caused by mutations in the<unk> 1 gene, located on chromosome 17q24.<unk>  catalyzes the first step of galactose phosphorylation in the Leloir pathway of intermediate metabolism.<unk>  is one of the three inborn errors of metabolism that lead to hypergalactosemia. The disorder is inherited as an autosomal recessive trait. Unlike classic galactosemia, which is caused by deficiency of galactose-1-phosphate uridyltransferase,<unk>  does not present with severe manifestations in early infancy. Its major clinical symptom is the development of cataracts during the first weeks or months of life, as a result of the accumulation, in the lens, of galactitol, a product of an alternative route of galactose utilization. The development of early cataracts in homozygous affected infants is fully preventable through early diagnosis and treatment with a galactose-restricted diet. Some studies have suggested that, depending on milk consumption later in life, heterozygous carriers of<unk>  may be prone to presenile cataracts at 20–50 years of age.
Galactokinase deficiency
Hexokinase deficiency
Galactose epimerase deficiency
Enolase deficiency
Glutaminase deficiency
Ornithine aminotransferase deficiency
Malonyl-CoA decarboxylase deficiency
Pyruvate kinase deficiency