High-Risk Screening for Fabry Disease: A Nationwide Study in Japan and Literature Review

Late-onset renal variant Fabry disease with R112H mutation and mild increase in plasma globotriaosylsphingosine: a case report

Fabry disease (FD) is an X-linked disorder resulting in a deficiency of α-galactosidase A (GLA) activity. The R112H mutation of GLA is relatively common in Japanese FD patients, characterized by a late-onset phenotype, almost normal to mild lyso-Gb3 elevation, and mild clinical symptoms, despite low GLA activity. This is due to the structural features of the R112H GLA protein. We herein report the case of a 42-year-old male patient with late-onset FD with a R112H mutation. The patient exhibited only renal involvement with no other organ damage and was successfully treated with galactosidase beta and subsequent migalastat for approximately 10 years. Especially, migalastat was clinically effective in normalizing plasma lyso-Gb3 levels and inhibiting the progression of renal damage associated with FD. Therefore, the use of migalastat in the FD patients with R112H mutation is highly recommended based on this case report.

Fabry disease and sleep disorders: a systematic review

Background

Fabry disease (FD) is an X-chromosome-linked disorder characterized by a reduced or complete absence of the enzyme α-galactosidase, resulting in the accumulation of lysosomal globotriaosylceramide. Despite the presence of these deposits in multiple organs, the problem of sleep disorders within this population has very rarely been documented.

Objective

This study aimed to investigate the types and prevalence of sleep disorders among patients with FD.

Methods

Screening of the following medical databases using key terms was performed on 10 February 2023: PubMed, Scopus, and Embase. A total of 136 records were identified. The quality assessment of the studies was conducted by using tools from the National Institutes of Health (NIH) and critical appraisal tools from the Joanna Briggs Institute (JBI).

Results

The study included nine studies on sleep disorders in patients with FD. The overall quality of the majority of these studies was assessed as either poor or fair. Among 330 patients, there was a slightly higher representation of female patients (56%). Sleep problems manifested 4-5 years after the onset of FD and sometimes even after 10-11 years. Genotypes of disease associated with sleep problems were rarely described. Within the FD population, the most commonly reported conditions were excessive daytime sleepiness (EDS) as well as obstructive and central sleep apnea (OSA, CSA). However, EDS occurred more frequently in FD patients, while the prevalence of OSA and CSA was within the ranges observed in the general population. The studies included indicated a lack of association between organ impairment by primary disease and EDS and OSA. The effectiveness of enzyme replacement therapy (ERT) in treating sleep disorders was not demonstrated.

Conclusion

The findings of this report revealed the presence of many sleep-related disorders within the FD population. However, very few studies on this subject are available, and their limited results make it difficult to truly assess the real extent of the prevalence of sleep disturbances among these individuals. There is a need to conduct further studies on this topic, involving a larger group of patients. It is important to note that there are no guidelines available for the treatment of sleep disorders in patients with FD.

High-risk screening for Fabry disease in hemodialysis patients in Chiba Prefecture, Japan

BACKGROUND

High-risk screening for Fabry disease in dialysis patients is an effective means for reducing the number of undiagnosed cases. However, such screening has not been conducted in Chiba Prefecture, Japan. Herein, we aimed to estimate the prevalence of Fabry disease among patients undergoing hemodialysis in Chiba Prefecture by high-risk screening using α-galactosidase A (αGal A) activity measurement, and examine the hemodialysis effect on αGal A activity.

METHODS

Patients who underwent maintenance hemodialysis at 25 facilities in Chiba Prefecture were recruited. The αGal A activity was measured using the dried blood spot (DBS) test as the first screening. If the enzyme activity was lower than the cut-off, the second screening was performed with the same method before and after dialysis.

RESULTS

Overall, 2924 patients (2036 men and 888 women) were included from which 94 cases (45 men and 48 women) showed decreased αGAL activity in the first screening and 3 (two men and one women) in the second screening. Genetic testing was performed in 3 patients, and the c.1078G > A mutation in GLA gene was detected in one male patient (0.03%). There has been a statistically significant decrease in αGal A activity of DBS at post-dialysis compared to that at pre-dialysis (20.5 ± 10.4 pmol/h/disk and 22.7 ± 11.5 pmol/h/disk, p < 0.0001).

CONCLUSION

The prevalence of Fabry disease among patients undergoing hemodialysis in Chiba Prefecture was estimated as 0.03%. This is the first time that dialysis has been shown to affect the αGal A activity.

A survey on the patient journey in Fabry disease in Japan

Background

Fabry disease (FD) is a rare X-linked lysosomal storage disease caused by a deficiency in α-galactosidase that is frequently diagnosed late after disease onset. While previous studies have focused on the multisystem manifestations that can lead to delayed or incorrect diagnosis and management, none have investigated the entire patient journey, and few have examined the patient's disease experience.

Objective

To investigate the path to diagnosis from disease onset, and the impact of the disease on daily life, among individuals with FD in Japan.

Methods

A nationwide survey of patients with FD receiving enzyme replacement therapy (ERT) was conducted between March 27 and June 11, 2018. Participants were recruited via patient support groups or physicians. Respondents completed a questionnaire eliciting information on sociodemographic status, self-perceived health status, initial and current clinical manifestations, the process of diagnosis, and impact on their life. Responses were analyzed descriptively.

Results

Data from 40 respondents were analyzed (17 males and 23 females; 77.5% aged ≥30 years). Mean ERT duration was 7.7 years. Mean time from disease onset to diagnosis was 18.7 years (16.7 years [males] vs 20.3 years [females]). The final diagnosis was made most commonly by pediatricians (38%). Forty percent of respondents felt relieved and 30% felt anxious when diagnosed, and when initiating ERT, 48% felt more positive about their daily life. Nevertheless, 85% reported that treatment affected their lives/work, and most (73%) experienced difficulties in their relationships with others.

Conclusion

Efforts are needed to achieve early diagnosis of patients with FD in Japan, to improve clinician awareness, and improve the psychosocial issues associated with FD.

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Fabry disease (FD) is a rare but commonly missed genetic disease.

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Efforts are needed to achieve early diagnosis of patients with FD in Japan.

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Patients with FD experience psychosocial issues and require increased support.

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Patients with FD need improved understanding about FD from the people around them.

Clinical Characteristics, Renal Involvement, and Therapeutic Options of Pediatric Patients With Fabry Disease

Inherited renal diseases represent 20% of the causes of end-stage renal diseases. Fabry disease, an X-linked lysosomal storage disorder, results from α-galactosidase A deficient or absent activity followed by globotriaosylceramide (Gb3) accumulation and multiorgan involvement. In Fabry disease, kidney involvement starts early, during intrauterine life by the Gb3 deposition. Even if chronic kidney disease (CKD) is discovered later in adult life in Fabry disease patients, a decline in glomerular filtration rate (GFR) can occur during adolescence. The first clinical sign of kidney involvement is represented by albuminuria. So, early and close monitoring of kidneys function is required: albuminuria and proteinuria, urinary albumin-to-creatinine ratio, serum creatinine, or cystatin C to estimate GFR, while urinary sediment with phase-contrast microscopy under polarized light may be useful in those cases where leucocyte α-Gal A activity and GLA genotyping are not available. Children with Fabry disease and kidney involvement should receive enzyme replacement therapy and nephroprotective drugs (angiotensin-converting enzyme inhibitors or angiotensin receptor blockers) to prevent or slow the progressive loss of kidney functions. Early diagnosis of Fabry disease is important as enzyme replacement therapy reduces symptoms, improves clinical features and biochemical markers, and the quality of life. More importantly, early treatment could slow or stop progressive organ damage in later life.