Segal S
Division of Biochemical Development and Molecular Diseases, Children's Hospital of Philadelphia, PA 19104, USA.
Eur J Pediatr. 1995;154(7 Suppl 2):S65-71. doi: 10.1007/BF02143806.
There is circumstantial evidence that defective galactosylation of complex glycoconjugates exists in tissues from galactosemic patients. Whether this is an etiologic factor in the long-term complications of the disorder is not known. Also not evident is the basis for the impaired galactosylation. The hypothesis that abnormally low cellular uridine diphosphate galactose (UDPgal) content is responsible has not been established. There is a tendency for galactosemic red cell UDPgal to be in the low normal range with a high uridine diphosphate glucose to UDP-gal ratio. This may reflect an inability of red cell UDPgal-4'-epimerase to maintain a normal ratio and consequently higher levels of UDPgal. In the more complex white blood cells and cultured fibroblasts, the UDPgal content and the uridine diphosphate glucose to UDPgal ratio of galactosemics are normal. Therefore, defective galactosylation observed in galactosemic fibroblasts must result from a defect in the transfer of galactose from UDPgal to these moieties.
有间接证据表明，半乳糖血症患者的组织中存在复合糖缀合物的半乳糖基化缺陷。这是否是该疾病长期并发症的病因尚不清楚。半乳糖基化受损的原因也不明确。细胞内尿苷二磷酸半乳糖（UDPgal）含量异常低是病因这一假设尚未得到证实。半乳糖血症患者红细胞中的UDPgal往往处于正常低限范围，尿苷二磷酸葡萄糖与UDPgal的比例较高。这可能反映出红细胞UDPgal-4'-表异构酶无法维持正常比例，从而导致UDPgal水平升高。在更复杂的白细胞和培养的成纤维细胞中，半乳糖血症患者的UDPgal含量以及尿苷二磷酸葡萄糖与UDPgal的比例是正常的。因此，在半乳糖血症成纤维细胞中观察到的半乳糖基化缺陷必定是由于半乳糖从UDPgal转移至这些部分的过程存在缺陷所致。
