大江 瑞恵

Newborn screening (NBS) for Fabry disease (FD) is an effective way to identify individuals with FD before the onset of symptoms, enabling early therapeutic treatment. The classic form of FD typically begins in early childhood or later, but the late-onset form often develops in adulthood. However, FD-NBS identifies positive cases regardless of the expected timing of symptom onset. Consequently, concerns have been raised about prolonged uncertainty, medicalization, and caregivers' hypervigilance throughout the asymptomatic period. These issues are particularly salient for mothers, who are often heterozygous carriers and primary caregivers. Despite the growing implementation of FD-NBS in some countries, the perspectives of parents, especially mothers, have not been adequately explored. This study explores the experiences, emotions, and needs of five mothers whose children were diagnosed with FD through NBS, aiming to uncover the psychological impact and support required during the asymptomatic period. Semistructured interviews were conducted and analyzed using the KJ (Kawakita Jiro) method, a kind of bottom-up qualitative approach. The findings revealed that mothers experienced a psychological burden related to monitoring for disease onset. However, this burden was reduced by several factors, including an understanding of the timing of onset, the attending physician's opinions, the passage of time, and personalized coping strategies. Needs were identified for support in understanding the disease, as well as for spaces that facilitate empathy and information exchange. Opinions regarding FD-NBS were generally positive; however, negative feelings were also expressed, including views that they did not have to discover their child's FD through NBS. These findings suggest that understanding the experiences of mothers of asymptomatic children and providing support, such as genetic counseling and peer support, could enhance the effectiveness of FD-NBS.

Structural analysis of small supernumerary marker chromosomes (sSMCs) has revealed that many have complex structures. Structural analysis of sSMCs by whole genome sequencing using short-read sequencers is challenging however because most present with a low level of mosaicism and consist of a small region of the involved chromosome. In this present study, we applied adaptive sampling using nanopore long-read sequencing technology to enrich the target region and thereby attempted to determine the structure of two sSMCs with complex structural rearrangements previously revealed by cytogenetic microarray. In adaptive sampling, simple specification of the target region in the FASTA file enables to identify whether or not the sequencing DNA is included in the target, thus promoting efficient long-read sequencing. To evaluate the target enrichment efficiency, we performed conventional pair-end short-read sequencing in parallel. Sequencing with adaptive sampling achieved a target enrichment at about a 11.0- to 11.5-fold higher coverage rate than conventional pair-end sequencing. This enabled us to quickly identify all breakpoint junctions and determine the exact sSMC structure as a ring chromosome. In addition to the microhomology and microinsertion at the junctions, we identified inverted repeat structure in both sSMCs, suggesting the common generation mechanism involving replication impairment. Adaptive sampling is thus an easy and beneficial method of determining the structures of complex chromosomal rearrangements.