Homozygous loss of a cysteine residue in the glucocerebrosidase gene results in Gaucher's disease with a hydropic phenotype

Transcriptomic Profiling of Egg Quality in Sea Bass (Dicentrarchus labrax) Sheds Light on Genes Involved in Ubiquitination and Translation

Variable and low egg quality is a major limiting factor for the development of efficient aquaculture production. This stems from limited knowledge on the mechanisms underlying egg quality in cultured fish. Molecular analyses, such as transcriptomic studies, are valuable tools to identify the most important processes modulating egg quality. However, very few studies have been devoted to this aspect so far. Within this study, the microarray-based transcriptomic analysis of eggs (of different quality) of sea bass (Dicentrarchus labrax) was performed. An Agilent oligo microarray experiment was performed on labelled mRNA extracted from 16 batches of eggs (each batch obtained from a different female) of sea bass, in which over 24,000 published probe arrays were used. We identified 39 differentially expressed genes exhibiting a differential expression between the groups of low (fertilization rate < 60 %) and high (fertilization rate > 60 %) quality. The mRNA levels of eight genes were further analyzed by quantitative PCR. Seven genes were confirmed by qPCR to be differentially expressed in eggs of low and high quality. This study confirmed the importance of some of the genes already reported to be potential molecular quality indicators (mainly rnf213 and irf7), but we also found new genes (mainly usp5, mem-prot, plec, cenpf), which had not yet been reported to be quality-dependent in fish. These results suggest the importance of genes involved in several important processes, such as protein ubiquitination, translation, DNA repair, and cell structure and architecture; these probably being the mechanisms that contribute to egg developmental competence in sea bass.

The clinical management of Type 2 Gaucher disease

Gaucher disease, the inherited deficiency of the enzyme glucocerebrosidase, is the most common of the lysosomal storage disorders. Type 2 Gaucher disease, the most severe and progressive form, manifests either prenatally or in the first months of life, followed by death within the first years of life. The rarity of the many lysosomal storage disorders makes their diagnosis a challenge, especially in the newborn period when the focus is often on more prevalent illnesses. Thus, a heightened awareness of the presentation of these rare diseases is necessary to ensure their timely consideration. This review, designed to serve as a guide to physicians treating newborns and infants with Gaucher disease, discusses the presenting manifestations of Type 2 Gaucher disease, the diagnostic work-up, associated genotypes and suggestions for management. We also address the ethical concerns that may arise with this progressive and lethal disorder, since currently available treatments may prolong life, but do not impact the neurological manifestations of the disease.

Two novel mutations in glucocerebrosidase, C23W and IVS7-1 G>A, identified in Type 1 Gaucher patients heterozygous for N370S

Gaucher disease is an autosomal recessive lysosomal storage disorder resulting from deficient glucocerebrosidase activity. There have been nearly 300 mutations described to date. Novel mutations can potentially provide insight into the biochemical basis of the disease. Two novel mutations are described in two Type 1 Gaucher patients with N370S compound heterozygosity; a point mutation that causes an amino acid substitution at cysteine residue 23 for tryptophan, and a second point mutation within the splicing element at the 3' end of intron 7. Both mutations were identified by PCR amplification and sequence analysis of patient glucocerebrosidase genomic DNA. Restriction fragment length polymorphism analysis was established for both novel mutations for efficient identification in future patients. Past literature suggests that mutations affecting cysteine residues involved in disulfide bridges, as well as mutations affecting splicing patterns of the glucocerebrosidase transcript, are detrimental to enzyme activity. However, compound heterozygosity with N370S, a mild mutation, will lead to a mild phenotype. The cases reported here support these past findings.

Novel frameshift mutation (Pro171fsX21) in neonatal type 2 Gaucher's disease

Gaucher's disease is caused by a deficiency of glucocerebrosidase (GBA) and results in the accumulation of glucocerebroside within macrophages. We report on a 33(+2) gestational week premature infant whose family history was significant for a previously undiagnosed premature sibling with similar clinical features, including severe hydrops fetalis, hepatosplenomegaly, skin lesions at birth followed by death. The diagnosis of Gaucher's disease type 2 in the present case was based on postmortem pathological findings and a subsequent gene analysis that indicated a heterozygous condition for the novel deletion mutation at GBA cDNA nucleotide position 630 resulting in the frameshift (Pro171fsX21) in exon 6 and a G→A transition mutation at GBA cDNA nucleotide position 887 (Arg257Gln) in exon 7.

Type 2 Gaucher disease: phenotypic variation and genotypic heterogeneity

Gaucher disease (GD), the most common lysosomal storage disease, results from a deficiency of the lysosomal enzyme glucocerebrosidase. GD has been classified into 3 types, of which type 2 (the acute neuronopathic form) is the most severe, presenting pre- or perinatally, or in the first few months of life. Traditionally, type 2 GD was considered to have the most uniform clinical phenotype when compared to other GD subtypes. However, case studies over time have demonstrated that type 2 GD, like types 1 and 3, manifests with a spectrum of phenotypes. This review includes case reports that illustrate the broad range of clinical presentations encountered in type 2 GD, as well as a discussion of associated manifestations, pathological findings, diagnostic techniques, and a review of current therapies. While type 2 GD is generally associated with severe mutations in the glucocerebrosidase gene, there is also significant genotypic heterogeneity.

Type 2 Gaucher disease: 15 new cases and review of the literature

OBJECTIVES

To provide a description of type 2 Gaucher disease. To attempt to define type 2 Gaucher disease within the spectrum of early-onset neuronopathic Gaucher disease.

BACKGROUND

Type 2 Gaucher disease is a rare disorder due to glucocerebrosidase deficiency that comprises a rapidly progressing neurological degeneration associated with visceral signs. Most data collected rely on the description of single cases or siblings. Cases of perinatal-lethal Gaucher disease are frequently considered as type 2 Gaucher patients, though the clinical presentation is different.

METHODS

We retrospectively studied the clinical history of 15 original acute Gaucher disease patients and reviewed the available data of 104 published cases of early-onset neuronopathic Gaucher disease, including 61 patients with the acute type and 43 cases of the perinatal-lethal form.

RESULTS

The neurological presentation of type 2 Gaucher disease is homogeneous and characterized by precocious, severe, and rapidly progressive brainstem degeneration in the foreground. The most frequent initial signs are hyperextension of the neck, swallowing impairment, and strabismus. Provoked asphyxic episodes generally appear in a second time. They are followed by prolonged spontaneous apneas that seem to be the main pejorative feature. Other neurological signs may be observed, but epilepsy, myoclonic epilepsy/myoclonus, trismus, stridor, and progressive microcephaly are less characteristic. Psychomotor regression may occur, but is not a typical feature of the disease onset. Chronic or subacute pulmonary disease predominates in the visceral involvement. Hepatosplenomegaly, failure to thrive, thrombocytopenia, and anemia are the other remarkable, albeit non-specific, features. The inflammatory component of Gaucher disease is underlined by the addition of unexplained fever to this systemic clinical picture. The natural history and particular signs of perinatal-lethal Gaucher disease do not belong to the type 2 Gaucher disease phenotype.

CONCLUSION

Type 2 Gaucher disease is a clinically homogeneous entity. The specificity of the neurological involvement is sufficient to suspect the diagnosis at the onset of the disease. Type 2 and perinatal-lethal Gaucher diseases are easily distinguishable in most cases.

Perinatal lethal Gaucher disease: a distinct phenotype along the neuronopathic continuum

Gaucher disease, the inherited deficiency of glucocerebrosidase, is characterized by significant genetic and phenotypic heterogeneity. At the extreme end of the phenotypic continuum is the perinatal lethal variant, typically presenting in utero or during the neonatal period as hydrops and/orcongenital ichthyosis, with severe and progressive neurological involvement. Insights from the null-allele Gaucher mouse model contributed to the identification of this distinct phenotype, which has unique epidermal involvement. While multiple mutations are encountered, many affected infants are homozygous for recombinant alleles. The diagnosis is often missed due to the early lethality and the failure to recognize the association between lysosomal disorders and hydrops fetalis. The incidence of severe perinatal Gaucher disease may prove more common than currently appreciated with greater physician awareness of the disorder.