Cataract and early nystagmus due to galactokinase deficiency

Excerpt

Galactokinase deficiency (GALK-D, OMIM #230200) is a very rare autosomal recessive inherited disorder in the first step of galactose metabolism presenting as bilateral cataract. The highest incidence is found in Bulgaria and in Bosnia, primarily in the Romani population with prevalent founder mutation p.P28T (Hennermann et al 2011). Our patient was the son of healthy, Slovak, non-consanquineous and non-Romani parents. The mother noticed fixation instability of both eyes of her child at the age of 2 months and at 8 months the ophtalmologic investigation revealed nystagmus and bilateral cataract (Fig. 1). Biochemical analysis showed hypergalactosuria 5.38 mmol/mol/creat (reference values <0.38) and excessive high excretion of galactitol in urine 18,672 mmol/mol creat (reference values <90). Molecular analysis revealed two novel mutations in the GALK1 gene: p.M307del (c.919_921del1ATG) and p.M1V (c.1A>G), so the patient was diagnosed as a compound heterozygote for GALK-D. The patient had no other abnormalities, reported in GALK-D (Bosch et al 2002). Nystagmus is a known consequence of infantile cataract, but it has not been described in patients with GALK-D. Its presence may indicate a worse visual outcome for the reported child (Lambert et al 2006). This child underwent cataract surgery on both eyes without any significant complication.

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