{
  "abstract": "RNU4-2 encodes U4 small nuclear RNA (snRNA), a non-coding RNA forming the spliceosome complex via the U4/U6 snRNA duplex. RNU4-2 heterozygous variants cause ReNU syndrome, which is characterised by intellectual disability, developmental delay, epilepsy, short stature and distinctive dysmorphic features. ReNU syndrome accounts for 0.4–0.5% of all cases of developmental delay, and RNU4-2 variants are located in the T-loop or stem III region of U4 snRNA, of which approximately 80% are the n.64_65insT variant in the T-loop. We identified four Japanese patients (4.3%) with novel and recurrent RNU4-2 variants from 93 individuals of developmental delay with negative results from exome sequencing. Genotype-phenotype correlations were observed in the present case series and a literature review. T-loop variants manifested severe developmental delay with more than 70% of cases being non-verbal. Stem III region variants resulted in milder developmental delay with fluent speech and nearly normal gross motor development milestones. In addition, we report a patient demonstrating intractable epilepsy with neurological regression harbouring a novel de novo heterozygous RNU4-2 variant (n.66A>G). This report expands the phenotypic spectrum of ReNU syndrome and suggests the presence of phenotypic variability related to variant location.",
  "authors": [
    {
      "affiliations": [
        "Division of Medical Genetics, Kanagawa Children’s Medical Center, Yokohama, Japan"
      ],
      "name": "Yukiko Kuroda"
    },
    {
      "affiliations": [
        "Division of Medical Genetics, Kanagawa Children’s Medical Center, Yokohama, Japan"
      ],
      "name": "Koki Nagai"
    },
    {
      "affiliations": [
        "Division of Medical Genetics, Kanagawa Children’s Medical Center, Yokohama, Japan"
      ],
      "name": "Yasuhiro Kawai"
    },
    {
      "affiliations": [
        "Clinical Research Institute, Kanagawa Children’s Medical Center, Yokohama, Japan"
      ],
      "name": "Takuya Naruto"
    },
    {
      "affiliations": [
        "Division of Neurology, Kanagawa Children’s Medical Center, Yokohama, Japan"
      ],
      "name": "Harutaka Saijou"
    },
    {
      "affiliations": [
        "Division of Neurology, Kanagawa Children’s Medical Center, Yokohama, Japan"
      ],
      "name": "Shotaro Morikawa"
    },
    {
      "affiliations": [
        "Division of Neurology, Kanagawa Children’s Medical Center, Yokohama, Japan"
      ],
      "name": "Tomohide Goto"
    },
    {
      "affiliations": [
        "Department of Pediatrics, Odawara Municipal Hospital, Odawara, Japan"
      ],
      "name": "Mutsumi Sato"
    },
    {
      "affiliations": [
        "Division of Medical Genetics, Kanagawa Children’s Medical Center, Yokohama, Japan"
      ],
      "name": "Kenji Kurosawa"
    }
  ],
  "title": "Genotype-phenotype correlations and phenotypic expansion in a case series of ReNU syndrome associated with RNU4-2 variants",
  "uid": "0c5f005d-4a1e-5256-86bb-69217c4f3bb9"
}