ALG6-CDG: a recognizable phenotype with epilepsy, proximal muscle weakness, ataxia and behavioral and limb anomalies.

INTRODUCTION: Alpha-1,3-glucosyltransferase congenital disorder of glycosylation (ALG6-CDG) is a congenital disorder of glycosylation. The original patients were described with hypotonia, developmental disability, epilepsy, and increased bleeding tendency. METHODS: Based on Euroglycan database registration, we approached referring clinicians and collected comprehensive data on 41 patients. RESULTS: We found hypotonia and developmental delay in all ALG6-CDG patients and epilepsy, ataxia, proximal muscle weakness, and, in the majority of cases, failure to thrive. Nine patients developed intractable seizures. Coagulation anomalies were present in <50 % of cases, without spontaneous bleedings. Facial dysmorphism was rare, but seven patients showed missing phalanges and brachydactyly. Cyclic behavioral change, with autistic features and depressive episodes, was one of the most significant complaints. Eleven children died before the age of 4 years due to protein losing enteropathy (PLE), sepsis, or seizures. The oldest patient was a 40 year-old Dutch woman. The most common pathogenic protein alterations were p.A333V and p.I299Del, without any clear genotype-phenotype correlation. DISCUSSION: ALG6-CDG has been now described in 89 patients, making it the second most common type of CDG. It has a recognizable phenotype and a primary neurologic presentation.

Lymphatic edema in congenital disorders of glycosylation.

Congenital disorders of glycosylation (CDG) are a group of metabolic disorders caused by deficient protein glycosylation. PMM2-CDG, the most common CDG, is caused by phosphomannomutase (PMM) deficiency. Clinical symptoms often include neurological involvement in addition to dysmorphic features, failure to thrive, cardiac failure, renal, and endocrine abnormalities. To our knowledge, lymphatic edema in CDG has not been reported. We present two cases of lymphatic edema in PMM2-CDG patients. The first patient was noted to have a larger right leg circumference at two years. Ultrasound investigations did not reveal any obvious vascular or lymphatic malformation. The swelling increased in size over time. At 12 years, lymphoscintigraphy revealed decreased lymphatic draining in both legs, which was more profound in the right leg. The second patient was treated for pulmonary stenosis at age 2 months. Postoperative, the patient suffered from protein-losing enteropathy, hypothyroidism, recurrent bacterial infections, and bilateral lymphatic edema. General condition improved after thyroxin treatment and albumin infusions; however, the bilateral pedal and leg edema remained unresolved. Contrast studies of the lymphatic system showed bilateral hypoplasia distal to the knees. Although both children had secondary factors worsening lymphatic edema in PMM2-CDG, hypoalbuminemia, recurrent infections, cardiac failure, and endocrine abnormalities could not fully explain the clinical features. The additional factors were treated successfully but the therapy did not resolve the lymphatic edema. Based on the abnormal imaging studies of the lymphatic system, we propose that lymphatic vessel hypoplasia is the major cause for lymphatic edema in our patients with PMM2-CDG.

An overview of L-2-hydroxyglutarate dehydrogenase gene (L2HGDH) variants: a genotype-phenotype study.

L-2-Hydroxyglutaric aciduria (L2HGA) is a rare, neurometabolic disorder with an autosomal recessive mode of inheritance. Affected individuals only have neurological manifestations, including psychomotor retardation, cerebellar ataxia, and more variably macrocephaly, or epilepsy. The diagnosis of L2HGA can be made based on magnetic resonance imaging (MRI), biochemical analysis, and mutational analysis of L2HGDH. About 200 patients with elevated concentrations of 2-hydroxyglutarate (2HG) in the urine were referred for chiral determination of 2HG and L2HGDH mutational analysis. All patients with increased L2HG (n=106; 83 families) were included. Clinical information on 61 patients was obtained via questionnaires. In 82 families the mutations were detected by direct sequence analysis and/or multiplex ligation dependent probe amplification (MLPA), including one case where MLPA was essential to detect the second allele. In another case RT-PCR followed by deep intronic sequencing was needed to detect the mutation. Thirty-five novel mutations as well as 35 reported mutations and 14 nondisease-related variants are reviewed and included in a novel Leiden Open source Variation Database (LOVD) for L2HGDH variants (http://www.LOVD.nl/L2HGDH). Every user can access the database and submit variants/patients. Furthermore, we report on the phenotype, including neurological manifestations and urinary levels of L2HG, and we evaluate the phenotype-genotype relationship.

Gastrointestinal and other clinical manifestations in 17 children with congenital disorders of glycosylation type Ia, Ib, and Ic.

OBJECTIVES: The typical signs and symptoms of congenital disorders of glycosylation (CDG) include dysmorphy, failure to thrive, and neurologic abnormalities. However, more and more children diagnosed at a young age are not dysmorphic and do not have neurologic involvement. The authors studied the gastrointestinal and other clinical manifestations of CDG type Ia, Ib, and Ic. METHODS: As of January 2003, 17 children were identified with CDG at the authors' institution. The medical records of the patients were reviewed. RESULTS: Five children had CDG Ia, three children CDG Ib, and nine children CDG Ic. Age at diagnosis ranged from 2 months to 15 years. Failure to thrive was present in 80% of patients with CDG Ia, in 66% of those with CDG Ib, and in 11% of those with CDG Ic. Five children had protein-losing enteropathy (two CDG Ia, two CDG Ib, and one CDG Ic). Hepatomegaly was present in 40% of patients with CDG Ia, in 66% of those with CDG Ib, and in 11% of those with CDG Ic. In CDG Ic, hepatomegaly was transient. In CDG Ia, histologic analysis of the liver showed swollen hepatocytes, steatosis, and fibrosis. In CDG Ib, hamartomatous collections of bile ducts were seen. In one patient with CDG Ib, the clinical picture was restricted to congenital hepatic fibrosis for more than a decade. CONCLUSIONS: The study confirms the heterogeneity of the clinical picture in children with CDG type Ia, Ib, and Ic. Children with protein-losing enteropathy should be tested for CDG. Protein-losing enteropathy can be caused, not only by CDG Ia and Ib, but also by type Ic. Children with congenital hepatic fibrosis should be tested for CDG, even in the absence of other symptoms. In CDG Ib, histologic analysis of the liver showed hamartomatous collections of bile ducts (Meyenburg complex).