Siblings with fucosidosis

An unusual presentation of fucosidosis in a Chinese boy: a case report and literature review (childhood fucosidosis)

Background

Fucosidosis is one of the rare autosomal recessive lysosomal storage diseases (LSDs) attributed to FUCA1 variants causing the deficiency of α-L-fucosidase in vivo. Α-L-fucosidase deficiency will cause excessive accumulation of fucosylated glycoproteins and glycolipids, which eventually leads to dysfunction in all tissue systems and presents with multiple symptoms. Fucosidosis is a rare disease which is approximately 120 cases have been reported worldwide (Wang, L. et al., J Int Med Res 48, 1-6, 2020). The number of reported cases in China is no more than 10 (Zhang, X. et al., J Int Med Res 49:3000605211005975, 2021).

Case presentation

The patient was an 8-year-old Chinese boy who presented with postnatal motor retardation, intellectual disability, short stature, language development retardation, coarse facial features, hepatomegaly, and diffuse angiokeratoma of both palms. His genetic testing showed the presence of a homozygous pathogenic variant (c.671delC) in the FUCA1 gene. In addition, the enzymatic activity of α-L-fucosidase was low. Ultimately, the patient was diagnosed with fucosidosis.

Conclusions

Fucosidosis is a rare lysosomal storage disease because of FUCA1 variants that cause the deficiency of α-L-fucosidase in vivo. An explicit diagnosis requires a combination of clinical manifestations, imaging examination, genetic testing and enzyme activity analysis. Early diagnosis plays an important role in fucosidosis.

Identification of a novel homozygous loss-of-function mutation in FUCA1 gene causing severe fucosidosis: A case report

Fucosidosis is a rare lysosomal storage disorder characterized by deficiency of α-L-fucosidase with an autosomal recessive mode of inheritance. Here, we describe a 4-year-old Chinese boy with signs and symptoms of fucosidosis but his parents were phenotypically normal. Whole exome sequencing (WES) identified a novel homozygous single nucleotide deletion (c.82delG) in the exon 1 of the FUCA1 gene. This mutation will lead to a frameshift which will result in the formation of a truncated FUCA1 protein (p.Val28Cysfs*105) of 132 amino acids approximately one-third the size of the wild type FUCA1 protein (466 amino acids). Both parents were carrying the mutation in a heterozygous state. This study expands the mutational spectrum of the FUCA1 gene associated with fucosidosis and emphasises the benefits of WES for accurate and timely clinical diagnosis of this rare disease.

Autism spectrum disorder in India: a scoping review

Autism is a grand challenge in global mental health to be dealt with on a priority basis. Phenotypic knowledge, biological understanding, and evidence-based intervention studies are all from western countries. We know very little about autism in the low- and middle-income countries (LMIC). Lack of infrastructure and difficulties in operationalizing research has widened the knowledge gap. We performed a comprehensive scoping review of research in Autism Spectrum Disorder in India to have an overall impression, identify gaps, and formulate evidence-based recommendations for further study. We searched PubMed, SCOPUS, and Cochrane Library to identify relevant Indian studies. A hundred and fifty-nine publications met the inclusion criteria. Most of the research contribution in autism is from few tertiary care medical centres, technological institutes, and not-for-profit organizations. We identified various themes of research like clinical profile, interventions, biomarkers, psychological, social, epidemiological, and risk factors. Evidence-based intervention studies, translation and adaptation of standard diagnostic instruments, and qualitative research on the experience of autism appeared to be state of the art. However, epidemiological studies, biomarkers identification, risk assessment studies were of low quality. There is a need for nationwide studies with representative sampling on epidemiology, biomarkers, and risk factors for a complete evaluation of the actual burden and biology of autism in India. Also, there is a need to design implementation research to evaluate the effectiveness of evidence-based interventions in routine healthcare settings. We recommend that future research should fill these gaps in understanding autism and improving its outcome in India.

Plasma α-L-fucosidase-1 in patients with Sjögren's syndrome and other rheumatic disorders

BACKGROUND

Human α-fucosidase (EC 3.2.1.51) is a hydrolase the importance of which has been increasing in the latest years. However, data about its plasma level in children with autoimmune disorders, particularly Sjögren's syndrome (SS), are lacking. In this study, the plasma activity of L-α-fucosidase-1 (α-L-FUCA-1) was assayed in hospitalized children and adults and its association with SS and other rheumatic disorders further evaluated.

METHODS

In total 73 Hungarian hospitalized patients, 32 children (2.5-10 years) and 41 adults (32-68 years), were enrolled in the study and underwent plasma assay of α-L-FUCA1 activity. Linear regression, Durbin-Watson (DW), and Pearson tests were evaluated to investigate the relationship between α-L-FUCA-1 plasma levels and autoimmune manifestations.

RESULTS

α-L-FUCA-1 correlated with SS both in children (2-sided t test, P = 0.0023) and in adults (2-sided t test, P = 0.00035). Linear regressions showed that in other rheumatic disorders, α-L-FUCA1 did not show any differential distribution related to the particular pathology (r = 0.2042, P = 0.1531, DW test = 2.2139 positive), while this trend was radically opposite for patients with SS (r = 0.1462, P = 0.0032, DW test = 1.3664, negative).

CONCLUSIONS

Alterations in plasma level of α-L-FUCA-1 were significantly associated with SS. This preliminary result should encourage further research on α-L-FUCA-1 as a possible differential serological marker of SS.

A novel homozygous frameshift mutation in the FUCA1 gene causes both severe and mild fucosidosis

AIMS

Fucosidosis is a rare autosomal recessive lysosomal storage disorder caused by α-L-fucosidase deficiency as a result of FUCA1 gene mutations. Here, we studied clinical features and the molecular basis of fucosidosis in a family from Iran, including two probands and nine family members.

METHODS

DNA sample of two probands were screened for gene defects using a next generation sequencing technique. The sequencing processes were performed on an Illumina Hiseq 4000 platform. Sequence reads were analysed using BWA-GATK.

RESULTS

Next generation sequencing revealed a frameshift mutation caused by 2 bp deletion (c.837_838 delTG; p.Cys279) in the FUCA1 gene. The identified mutation was tested in all participants. Homozygous patients had almost all the complications associated with fucosidosis, while heterozygous carriers were unaffected.

CONCLUSIONS

The variant c.837_838 delTG; p.Cys279 has not been reported previously and is predicted to be pathogenic due to a premature stop codon.