There are nine human herpesviruses (HHVs). Herpes simplex virus (HSV) and varicella-zoster virus (VZV) belong to Alphaherpesvirinae, which has neurotrophy. As recent topics, an association with autoimmune encephalitis after HSE has been reported for HSV, and for VZV, an increase in central nervous system (CNS) complications is concerned due to an increase in herpes zoster.

  HHV-6, which is one of Betaherpesvirinae, is a lymphotropic HHV. Recently, HHV-6 has been implicated in medial temporal lobe sclerosis, which is an intractable epilepsy. In addition, FilmArray^® Meningitis and Encephalitis Panel was covered by insurance in Japan in October 2022, facilitating the detection of HHV-6 in cerebrospinal fluid. However, since HHV-6 latently infects mononuclear cells, it must be taken care to detect HHV-6 latently infecting mononuclear cells in CSF or HHV-6 incorporated into host chromosomes and to distinguish it from active infection.

  Epstein-Barr virus, which is one of Gammaherpesvirinae, is also a lymphotropic HHV, but its involvement with multiple sclerosis has recently been reported.

  Thus, many topics on various HHVs and CNS diseases have been reported in recent years. In this article, these HHV and CNS disease topics will be reviewed.

  Objective: With the availability of approved treatments for spinal muscular atrophy (SMA), early diagnosis and treatment are considered important and newborn screening (NBS) has commenced in some regions. From April 2022 to March 2023, expanded NBS for SMA and immunodeficiency was studied in Tochigi Prefecture. Methods: A real-time PCR method was performed using reagents capable of simultaneously detecting the SMN1 gene, causes SMA, and TREC and KREC, markers for immunodeficiency. Results: 10,738 of all newborns were screened. Detailed clinical examinations were undertaken in suspected cases of SMA (n＝1) and immunodeficiency (n＝4) and confirmed one case each of SMA and secondary immunodeficiency ; the remaining three cases were normal. At 16 days of age, the female patient with SMA had 0 and 3 copies of SMN1 and SMN2, respectively, and anti-AAV9 antibody titers ＞1 : 200. Before gene therapy, the patient’s muscle tone and strength and deep tendon reflexes were normal ; the CHOP INTEND was 30 points, and the CMAP of the median nerve was 1.2 mV, which were lower than the reference value. As the patient tested positive for anti-AAV9 antibody, from 23 days after birth, she was treated with nusinersen five times. At 8 months of age, the patient tested negative for anti-AAV9 antibody and initiated treatment with onasemnogene abeparvovec. At 1 year and 4 months of age, the patient was able to walk independently. Conclusions: In this case, early treatment resulted in almost typical development. NBS was shown to be useful. Therefore, accumulation of early diagnosis and treatment cases will facilitate the commercial availability of extended NBS to enable early treatment and effective management.