A new variant neuropathic type of Gaucher's disease characterized by hydrocephalus, corneal opacities, deformed toes, and fibrous thickening of spleen and liver capsules

The genetic basis of hydrocephalus: genes, pathways, mechanisms, and global impact

Hydrocephalus (HC) is a heterogenous disease characterized by alterations in cerebrospinal fluid (CSF) dynamics that may cause increased intracranial pressure. HC is a component of a wide array of genetic syndromes as well as a secondary consequence of brain injury (intraventricular hemorrhage (IVH), infection, etc.) that can present across the age spectrum, highlighting the phenotypic heterogeneity of the disease. Surgical treatments include ventricular shunting and endoscopic third ventriculostomy with or without choroid plexus cauterization, both of which are prone to failure, and no effective pharmacologic treatments for HC have been developed. Thus, there is an urgent need to understand the genetic architecture and molecular pathogenesis of HC. Without this knowledge, the development of preventive, diagnostic, and therapeutic measures is impeded. However, the genetics of HC is extraordinarily complex, based on studies of varying size, scope, and rigor. This review serves to provide a comprehensive overview of genes, pathways, mechanisms, and global impact of genetics contributing to all etiologies of HC in humans.

Metabolic Cardiomyopathies and Cardiac Defects in Inherited Disorders of Carbohydrate Metabolism: A Systematic Review

Heart failure (HF) is a progressive chronic disease that remains a primary cause of death worldwide, affecting over 64 million patients. HF can be caused by cardiomyopathies and congenital cardiac defects with monogenic etiology. The number of genes and monogenic disorders linked to development of cardiac defects is constantly growing and includes inherited metabolic disorders (IMDs). Several IMDs affecting various metabolic pathways have been reported presenting cardiomyopathies and cardiac defects. Considering the pivotal role of sugar metabolism in cardiac tissue, including energy production, nucleic acid synthesis and glycosylation, it is not surprising that an increasing number of IMDs linked to carbohydrate metabolism are described with cardiac manifestations. In this systematic review, we offer a comprehensive overview of IMDs linked to carbohydrate metabolism presenting that present with cardiomyopathies, arrhythmogenic disorders and/or structural cardiac defects. We identified 58 IMDs presenting with cardiac complications: 3 defects of sugar/sugar-linked transporters (GLUT3, GLUT10, THTR1); 2 disorders of the pentose phosphate pathway (G6PDH, TALDO); 9 diseases of glycogen metabolism (GAA, GBE1, GDE, GYG1, GYS1, LAMP2, RBCK1, PRKAG2, G6PT1); 29 congenital disorders of glycosylation (ALG3, ALG6, ALG9, ALG12, ATP6V1A, ATP6V1E1, B3GALTL, B3GAT3, COG1, COG7, DOLK, DPM3, FKRP, FKTN, GMPPB, MPDU1, NPL, PGM1, PIGA, PIGL, PIGN, PIGO, PIGT, PIGV, PMM2, POMT1, POMT2, SRD5A3, XYLT2); 15 carbohydrate-linked lysosomal storage diseases (CTSA, GBA1, GLA, GLB1, HEXB, IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, ARSB, GUSB, ARSK). With this systematic review we aim to raise awareness about the cardiac presentations in carbohydrate-linked IMDs and draw attention to carbohydrate-linked pathogenic mechanisms that may underlie cardiac complications.

A rare cause of hydrops fetalis in two Gaucher disease type 2 patients with a novel mutation

Gaucher disease type 2 is the most progressive and the rarest form of Gaucher disease, defined as the acute neuronopathic type. We presented two GD2 patients who died before three months of age due to severe septicemia, respiratory and liver failure. One was homozygous for a novel GBA variant c.590 T > A (p.197 K), and the second homozygous for the known GBA mutation c.1505G > A (p.R502H). Ichthyosis, hydrops fetalis, apnea, myoclonic seizures, and hepatosplenomegaly occurred in both patients, but hypertrophic cardiomyopathy was observed only in the second and unilateral cataract in the first patient. Due to the disease's early and rapid neurological progression, we did not administer ERT to our patients. It is strongly believed that early diagnosis is essential, and prenatal diagnosis makes genetic counselling possible for future pregnancies.

A comprehensive monocentric ophthalmic study with Gaucher disease type 3 patients: vitreoretinal lesions, retinal atrophy and characterization of abnormal saccades

Background

The differentiation between Gaucher disease type 3 (GD3) and type 1 is challenging because pathognomonic neurologic symptoms may be subtle and develop at late stages. The ophthalmologist plays a crucial role in identifying the typical impairment of horizontal saccadic eye movements, followed by vertical ones. Little is known about further ocular involvement. The aim of this monocentric cohort study is to comprehensively describe the ophthalmological features of Gaucher disease type 3. We suggest recommendations for a set of useful ophthalmologic investigations for diagnosis and follow up and for saccadometry parameters enabling a correlation to disease severity.

Methods

Sixteen patients with biochemically and genetically diagnosed GD3 completed ophthalmologic examination including optical coherence tomography (OCT), clinical oculomotor assessment and saccadometry by infrared based video-oculography. Saccadic peak velocity, gain and latency were compared to 100 healthy controls, using parametric tests. Correlations between saccadic assessment and clinical parameters were calculated.

Results

Peripapillary subretinal drusen-like deposits with retinal atrophy (2/16), preretinal opacities of the vitreous (4/16) and increased retinal vessel tortuosity (3/16) were found. Oculomotor pathology with clinically slowed saccades was more frequent horizontally (15/16) than vertically (12/16). Saccadometry revealed slowed peak velocity compared to 100 controls (most evident horizontally and downwards). Saccades were delayed and hypometric. Best correlating with SARA (scale for the assessment and rating of ataxia), disease duration, mSST (modified Severity Scoring Tool) and reduced IQ was peak velocity (both up- and downwards). Motility restriction occurred in 8/16 patients affecting horizontal eye movements, while vertical motility restriction was seen less frequently. Impaired abduction presented with esophoria or esotropia, the latter in combination with reduced stereopsis.

Conclusions

Vitreoretinal lesions may occur in 25% of Gaucher type 3 patients, while we additionally observed subretinal lesions with retinal atrophy in advanced disease stages. Vertical saccadic peak velocity seems the most promising “biomarker” for neuropathic manifestation for future longitudinal studies, as it correlates best with other neurologic symptoms. Apart from the well documented abduction deficit in Gaucher type 3 we were able to demonstrate motility impairment in all directions of gaze.

Ophthalmic manifestations of Gaucher disease: the most common lysosomal storage disorder

Gaucher disease (GD) results from a deficiency of glucocerebrosidase activity and the subsequent accumulation of the enzyme's metabolites, principally glucosylsphingosine and glucosylceramide. There are three principal forms: Type I, which is the most common, is usually considered non-neuronopathic. Type II, III and IIIc manifest earlier and have neurological sequelae due to markedly reduced enzyme activity. Gaucher's can be associated with ophthalmological sequelae but these have not been systematically reviewed. We therefore performed a comprehensive literature review of all such ophthalmic abnormalities associated with the different types of Gaucher disease. We systematically searched the literature (1950 - present) for functional and structural ocular abnormalities arising in patients with Gaucher disease and found that all subtypes can be associated with ophthalmic abnormalities; these range from recently described intraocular lesions to disease involving the adnexae, peripheral nerves and brain. In summary, Gaucher can affect most parts of the eye. Rarely is it sight-threatening; some but not all manifestations are amenable to treatment, including with enzyme replacement and substrate reduction therapy. Retinal involvement is rare but patients with ocular manifestations should be monitored and treated early to reduce the risk of progression and further complications. As Gaucher disease is also associated with Parkinsons disease and may also confer an increased risk of malignancy (particularly haematological forms and melanoma), any ocular abnormalities should be fully investigated to exclude these potential underlying conditions.

Surgery for gastroesophageal reflux disease with Gaucher disease type 2

Gaucher disease, the most common lysosomal storage disease, is sometimes complicated with gastroesophageal reflux disease (GERD). The present patient was a 136-day-old Japanese boy with Gaucher disease type 2. Enzyme replacement therapy and chemical chaperone therapy were successful for the skin disorders, joint contractures, hepatosplenomegaly and thrombocytopenia, but he also had GERD. Accordingly, a Nissen fundoplication with gastrostomy was performed. There was no vulnerability of organs, easy bleeding or difficulty of maintaining the visual field because of hepatosplenomegaly during operation. In the perioperative period, there was no prolonged wound healing or infection. GERD was improved. In the near future, the number of long-term survivors of Gaucher disease will increase due to improvements in medical therapy. Therefore, it is expected that the number of patients requiring fundoplication will also increase. In patients with successful medical therapy, surgical fundoplication can be safely and effectively performed.

Corneal manifestations and in vivo confocal microscopy of Gaucher disease

PURPOSE

To report corneal abnormalities and confocal microscopy findings in a patient with a variant of Gaucher disease (GD).

METHODS

Case report with slit-lamp photography, confocal microscopy, and molecular analysis of the glucocerebrosidase gene.

RESULTS

Ophthalmic evaluation in a 57-year-old white patient demonstrated corneal opacities scattered throughout the cornea. Confocal microscopy revealed a completely distorted stromal architecture. The anterior part showed keratocytes with an abnormal morphology intermingled with minute white dots. In the posterior part, normal keratocytes were virtually absent and replaced by hyperreflective rod-like structures. Analysis of the glucocerebrosidase gene disclosed a heterozygous F216Y/L444P mutation. The patient's old records revealed that these corneal abnormalities were already present at the age of 16 years, almost 15 years before the diagnosis of GD was made. His 2 siblings known with the same disorder and mutations also showed abnormal visual acuity and increased central corneal thickness. The confocal microscopy demonstrated some subclinical abnormalities, but otherwise normal corneas.

CONCLUSIONS

Our patient had an unusual mutation responsible for his GD. Although corneal opacities are virtually unknown in GD, except in the D409H homozygous cardiovascular subtype, this patient had marked corneal stromal abnormalities.

Gaucher disease with communicating hydrocephalus and cardiac involvement

A 14-year-old female with Gaucher disease presented with hydrocephalus, corneal opacities, cirrhosis, and cardiac valvular involvement. A homozygous D409H mutation was identified. She underwent surgery for aortic and mitral valve replacement. Because of severe calcification of the aortic root, no successful valve replacement was performed. She died on the third day after the explorative cardiac surgery. Cardiac abnormalities represent a life-threatening presentation of the homozygous D409H mutation. Identification of this type is essential prior to initiating appropriate therapy with enzyme replacement and cardiac corrective surgery.

Management of neuronopathic Gaucher disease: revised recommendations

The original guidelines drawn up for the management of the neuronopathic forms of Gaucher disease were felt to be in need of revision; in particular, the role of high-dose enzyme replacement therapy (120 IU/kg of body weight every 2 weeks) in stabilizing neurological disease. The existing published evidence was analysed; it was concluded that it did not support the role of high-dose ERT, although this might be required to treat severe visceral disease.

Lysosomal storage disorders in the newborn

Lysosomal storage disorders are rare inborn errors of metabolism, with a combined incidence of 1 in 1500 to 7000 live births. These relatively rare disorders are seldom considered when evaluating a sick newborn. A significant number of the >50 different lysosomal storage disorders, however, do manifest in the neonatal period and should be part of the differential diagnosis of several perinatal phenotypes. We review the earliest clinical features, diagnostic tests, and treatment options for lysosomal storage disorders that can present in the newborn. Although many of the lysosomal storage disorders are characterized by a range in phenotypes, the focus of this review is on the specific symptoms and clinical findings that present in the perinatal period, including neurologic, respiratory, endocrine, and cardiovascular manifestations, dysmorphic features, hepatosplenomegaly, skin or ocular involvement, and hydrops fetalis/congenital ascites. A greater awareness of these features may help to reduce misdiagnosis and promote the early detection of lysosomal storage disorders. Implementing therapy at the earliest stage possible is crucial for several of the lysosomal storage disorders; hence, an early appreciation of these disorders by physicians who treat newborns is essential.

Glucosylceramide transfer from lysosomes--the missing link in molecular pathology of glucosylceramidase deficiency: a hypothesis based on existing data

Gaucher disease (GD), deficiency of acid glucosylceramidase (GlcCer-ase) is characterized by deficient degradation of beta-glucosylceramide (GlcCer). It is well known that, in GD, the lysosomal accumulation of uncleaved GlcCer is limited to macrophages, which are gradually converted to storage cells with well known cytology--Gaucher cells (GCs). On the basis of previous studies of the disorder and of a comparison with other lysosomal enzymopathies affecting degradation of the GlcCer-based glycosphingolipid series, it is hypothesized that in other cell types (i.e. non-macrophage cells) the uncleaved GlcCer, in GlcCer-ase deficiency, is transferred to other cell compartments, where it may be processed and even accumulated to various degrees. The consequence of the abnormal extralysosomal load may differ according to the cell type and compartment targeted and may be influenced by genetically determined factors, by a number of acquired conditions, including the current metabolic situation. The sequelae of the uncleaved GlcCer extralysosomal transfer may range from probably innocent or positive stimulatory, to the much more serious, in which it interferes with a variety of cell functions, and in extreme cases, can lead to cell death. This alternative processing of uncleaved GlcCer may help to explain tissue alterations seen in GD that have, so far, resisted explanation based simply on the presence of GCs. Paralysosomal alternative processing may thus go a long way towards filling a long-standing gap in the understanding of the molecular pathology of the disorder. The impact of this alternative process will most likely be inversely proportional to the level of residual GlcCer-ase activity. Lysosomal sequestration of GlcCer in these cells is either absent or in those exceptional cases where it does occur, it is exceptional and rudimentary. It is suggested that paralysosomal alternative processing of uncleaved GlcCer is the main target for enzyme replacement therapy. The mechanism responsible for GlcCer transfer remains to be elucidated. It may also help in explaining the so far unclear origin of glucosylsphingosine (GlcSph) and define the mutual relation between these two processes.

Neonatal Gaucher disease presenting as persistent thrombocytopenia

Mutations in the beta-glucocerebrosidase gene cause Gaucher disease with the type 1 variant generally presenting later in life with mild disease and type 2 in infancy with severe neuronopathic symptoms. We describe a neonate homozygous for the D409 H mutation with thrombocytopenia, splenomegaly and cholestasis at birth as the major features.

Gaucher disease: in vivo evidence for allele dose leading to neuronopathic and nonneuronopathic phenotypes

Gaucher disease, a common lysosomal storage disorder, is associated with mutations at the acid beta-glucosidase (GCase) locus. Two affected individuals are described to share a common mutant allele, but manifest different clinical categorical phenotypes. A 57-year-old female, with Gaucher disease type 1 and Cherokee ancestry, was homozygous for a rare mutant allele encoding Lys79Asn (K79N). A 2-year-old Caucasian male, with Gaucher disease type 3 and Cherokee ancestry, was a heteroallelic homozygote for this same allele (K79N) and a novel complex mutation (null allele). The shared alleles were identical as determined by complete gene sequencing, suggesting a founder effect. The discrepant phenotypes (types 1 and 3) in these two patients provide support for a threshold of residual activity necessary to "protect" the central nervous system (CNS) from the pathogenic effects of Gaucher disease, indicating an allele dose-effect. Designation of genotype associations with specific phenotypes must be assessed with this perspective.

Variant Gaucher disease characterized by dysmorphic features, absence of cardiovascular involvement, laryngospasm, and compound heterozygosity for a novel mutation (D409H/C16S)

A 20-month-old girl with developmental delay, dysmorphic features, horizontal supranuclear gaze palsy, retrocollis, and episodes of laryngospasm was diagnosed with variant neuronopathic Gaucher disease. The diagnosis was made enzymatically. Mutation analysis showed compound heterozygosity for D409H and a previously unreported mutation C16S. The presence of dysmorphic features, laryngospasm, absent cardiac findings, and the severe clinical phenotype distinguishes our case from other cases of variant neuronopathic Gaucher disease. We therefore propose to extend the spectrum of variant Gaucher disease.