ALG12-congenital disorder of glycosylation (ALG12-CDG) is a rare disorder caused by a deficiency of dolichol-P-mannose:Man7GlcNAc2-PP-dolichyl-α-6-mannosyltransferase which presents with intellectual disability, hypotonia, dysmorphic features, low IgG levels with recurrent infections, male genital hypoplasia, and coagulation abnormalities. We report a unique family with three affected individuals, including two older brothers with only cognitive and coagulation defects and a younger brother who died from a severe multisystem disease at age 18 months. The two living brothers are the oldest and mildest cases of ALG12-CDG described thus far. Whole exome sequencing of the older brothers revealed a previously described c.1001delA (p.N334TfsX15) pathogenic variant and a c.671C > T (p.T224 M) variant of uncertain significance in ALG12. Our cases broaden the recognized genetic and phenotypic spectrum of this disorder and suggest a role for other genetic and environmental factors in modulating disease phenotype.

BACKGROUND: POMT2 mutations have been identified in Walker-Warburg syndrome or muscle-eye-brain-like, but rarely in limb girdle muscular dystrophy (LGMD).
RESULTS: Two POMT2 mutations, one null and one missense, were found in a patient with LGMD and mild mental impairment, no brain or ocular involvement, minor histopathological features, and slight reduction of α-dystroglycan (α-DG) glycosylation and α-DG laminin binding.
CONCLUSIONS: Our case, the fourth LGMD POMT2-mutated reported to date, provides further evidence of correlation between level of α-DG glycosylation and phenotype severity.

Congenital disorders of glycosylation (CDG) are a growing group of inherited metabolic disorders where enzymatic defects in the formation or processing of glycolipids and/or glycoproteins lead to variety of different diseases. The deficiency of GDP-Man:GlcNAc2-PP-dolichol mannosyltransferase, encoded by the human ortholog of ALG1 from yeast, is known as ALG1-CDG (CDG-Ik). The phenotypical, molecular and biochemical analysis of a severely affected ALG1-CDG patient is the focus of this paper. The patient\'s main symptoms were feeding problems and diarrhea, profound hypoproteinemia with massive ascites, muscular hypertonia, seizures refractory to treatment, recurrent episodes of apnoea, cardiac and hepatic involvement and coagulation anomalies. Compound heterozygosity for the mutations c.1145T>C (M382T) and c.1312C>T (R438W) was detected in the patient\'s ALG1-coding sequence. In contrast to a previously reported speculation on R438W we confirmed both mutations as disease-causing in ALG1-CDG.

Walker-Warburg syndrome (WWS) is a rare, lethal genetic disease associated with a cobblestone-type lissencephaly, eye abnormalities, and a type of muscular dystrophy. There is a wide spectrum of brain and eye defects associated with this diagnosis; therefore, this diagnosis may not initially be considered. This diagnosis is especially difficult for families because there is no treatment available and management of the condition is supportive only. Parents of an infant with WWS need to be shown support and empathy while they are dealing with the sorrow of a terminal illness. Use of a nursing model, \"Middle range theory of chronic sorrow,\" will be instrumental in assisting staff as they care for the patient and the patient\'s family. They also need to be guided toward receiving genetic counseling to weigh their options for future family planning as the risk of another WWS pregnancy is 25%.

Walker--Warburg syndrome (WWS), the most severe alpha-dystroglycanopathy, is characterized by brain and eye anomalies, and congenital muscular dystrophy (CMD). So far at least four genes (POMT1, POMT2, Fukutin, and FKRP gene) have been implicated in WWS, accounting for about 30% of all cases. We report a male patient with WWS resulting from a homozygous nonsense mutation (R514X) in the POMT1 gene. The patient had congenital hydrocephalus which was detected at 29 weeks of gestation. A brain MRI obtained after birth revealed type II lissencephaly, hydrocephalus, and pontocerebellar hypoplasia. The case also exhibited severe ocular malformations and muscular hypotonia due to CMD.

A defect of the dolichyl-P-Man:Man5GlcNAc2-PP-dolichyl mannosyltransferase encoded by the ALG3 gene (alias NOT56L) causes congenital disorder of glycosylation type Id (CDG-Id). In this work, a new mutation in the ALG3 gene causing atypical splicing is described with characterization of expression levels and transcript stabilities of the different splice products. A silent mutation in exon 1 of the ALG3 gene (c.165C