Status of children and caregivers with Bloom syndrome and Rothmund–Thomson syndrome in Japan

Bloom syndrome (BS) and Rothmund–Thomson syndrome (RTS) are caused by pathogenetic variants in the BLM and RECQL4 genes, which belong to the RecQ helicase family. BS is characterized by short stature, sun-sensitive erythema, immunodeficiency, and a predisposition to various malignancies. RTS is characterized by poikiloderma, bone malformations, and a predisposition to osteosarcoma. In our previous studies, approximately 10 cases of each condition were reported in Japan; however, most of the reported cases involved adults. To elucidate the current state of children and caregivers of patients with BS and RTS in Japan, we conducted a questionnaire-based study. We received responses from four guardians of children with BS and five of those with RTS, all of whom were members of family association of BS or RTS in Japan. None of the children had been included in previous studies. All patients were low birth weight infants (under 2300 g), and one child with BS was classified as extremely low birth weight. With the exception of one child with BS, all received growth hormone replacement therapy; no children with RTS received growth hormone treatment. The height of children with BS tended to be shorter than those with RTS. Most children with BS or RTS visited the hospital once a month. Blood tests and ultrasonography were commonly used for malignancy surveillance. Three of the five RTS guardians did not recognize characteristic skin lesions such as poikiloderma. Although sun sensitivity was not prominent, nearly all children with RTS used sunscreen. One child with RTS developed osteosarcoma. BS was considered to impose a greater psychological burden on parents than RTS. This study clarified the needs and challenges faced by children with BS and RTS and their families in Japan. Understanding the true status and needs of these patients and their caregivers will help improve their quality of life.