Carbohydrate-deficient glycoprotein syndrome type 2

Abstract

The carbohydrate-deÐcient glycoprotein syndromes (CDGS) are multisystem disorders caused by defects of glycosylation of various glycoproteins (McKusick 212066). Biochemically, four types have been classiÐed so far based on di†erent patterns in isoelectric focusing of transferrin. To our knowledge, only two patients with CDGS type 2 have been described (Jaeken et al 1991 ; Ramaekers et al 1991). In both children, decreased activities of the Golgi enzyme N-acetylglucosaminyltransferase II (EC 2.4.1.143) were found, caused by di†erent point mutations in the encoding gene on chromosome 14q21 (Jaeken et al 1994 ; Tan et al 1996). We report a third case with CDGS type 2. This girl is the only child of healthy, nonconsanguineous, caucasian parents. Pregnancy and birth were normal. During the Ðrst months of life, motor inactivity and clumsiness became apparent ; the head circumference dropped from P50 to P3. Features were dysmorphic with brachycephalus, protruding metopic suture, hypertelorism, epicanthus, broad nose and mouth, large ears and a large intermamillary distance with slightly inverted nipples. Her psychomotor development was delayed : at the age of 24 months, she could speak only a few words and pulled to standing. Neurologically, the girl showed mild truncal hypotonia, normal deep tendon reÑexes, an intermittent squint and stereotyped behaviour with head bobbing. EEG revealed generalized spike-wave and poly-spike-wave complexes ; visual evoked potentials were delayed (130 ms). Motor nerve conduction velocity, electromyography and acoustic evoked potentials were normal. Cranial MRI showed slightly enlarged ventricles and subarachnoid spaces ; pons and cerebellum were of normal size. Abdominal sonography and echocardiography were normal. Abnormal laboratory values were ASAT 115 U/L (adult reference \19), CPK 128 U/L (adult reference \70), haptoglobin \5 mg/dl (adult reference 30È200), PTT 47 s (reference \40), factor VII 57% (70È130), factor IX 64% (70È140), factor XI 40% (70È120), antithrombin III 43% (80È120), protein C 62% (70È130). The karyogram revealed a variant of chromosome 9 (46, XX, var(9)(q12), GTG). Carbohydrate-deÐcient transferrin was [10 mg/L (reference 0.8È1.6) ; isoelectric focusing (IEF) of transferrin (western blot) showed the typical pattern of CDGS type 2 with mainly disialotransferrin, slightly increased monosialotransferrin and an almost completely missing tetrasialotransferrin. IEF of transferrin in both parents was normal. The two previously reported patients with CDGS type 2 showed a similar clinical

DOI: 10.1023/A:1005422610091

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@article{Engelhardt1999CarbohydratedeficientGS, title={Carbohydrate-deficient glycoprotein syndrome type 2}, author={Hubertus Engelhardt and Mareike Staudt and Alexandra L. Haessler and U. Holzbach and Peter Freisinger and Ingeborg Kr{\"a}geloh-Mann}, journal={Journal of Inherited Metabolic Disease}, year={1999}, volume={22}, pages={192-193} }