Categories: Homeostasis / metabolism phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 230400 (trait) , 606999 (gene)

Links to relevant human diseases in MONDO:

• MONDO:0018116: galactosemia

Single-gene trait/disorder: yes

Disease-related: no

Key variant known: no

Cross-species summary: Galactosaemia/Galactosemia is characterized by impaired galactose metabolism resulting in mild to severe clinical signs. Milder forms can cause cataract.

Species summary: Considering that macropod species produce milk with a very low lactose content and that pouch-young kangaroo have a low intestinal lactase content, Stephens et al. (1974) hypothesised that macropod species may not utilise galactose and have a galactose metabolism deficiency. The authors measured galactokinase and galactose1-phosphate uridyl transferase (GPUT) in two macropod species - the grey (Macropus giganteus) and the red kangaroo (Megaleia rufa). "In both red and grey kangaroos, galactokinase activity was about one-sixth of the normal human value. ... . A distinct difference between the two species was observed with regard to transferase, in that the grey kangaroo almost completely lacked this enzyme, whereas the red kangaroos had levels approximating those in humans heterozygous for GPUT deficiency."
Richardson at al. (1979) tested Western grey kangaroos (Macropus fuliginosus) and found them to have “no detectable GPUT [Galactose-1 phosphate uridyl transferase] activity as measured by the standard spectrophotometric assay procedure.” They concluded that “the absence of normal levels of enzyme from all the animals tested from eastern Australia (Macropus fuliginosus melanops), from western Australia (M.f. ocydromus) and from Kangaroo Island (M.f. fuliginosus) makes it likely that the deficiency allele is fixed in this species.” [IT thanks Emma Faull for contributions to this entry in September 2025] 

Clinical features: Stephens et al. (1974) observed “diarrhoea and occasional cataract formation in bottle-fed orphan pouch-young kangaroos.”