Newborn Screening for Spinal Muscular Atrophy: A 2.5-Year Experience in Hyogo Prefecture, Japan.

Newborn screening (NBS) for spinal muscular atrophy (SMA) is necessary, as favorable outcomes can be achieved by treatment with disease-modifying drugs in early infancy. Although SMA-NBS has been initiated in Japan, its clinical results have not been fully reported. We report the findings of the initial 2.5 years of a pilot SMA-NBS of approximately 16,000 infants conducted from February 2021 in Hyogo Prefecture, Japan. Clinical data of 17 infants who tested positive were retrospectively obtained from the NBS follow-up centers participating in this multicenter cohort observational study. Genetic testing revealed 14 false positives, and three infants were diagnosed with SMA. Case 1 had two copies of survival motor neuron (SMN) 2 and showed SMA-related symptoms at diagnosis. Case 2 was asymptomatic, with two copies of SMN2. Asymptomatic case 3 had four copies of SMN2 exon 7, including the SMN1/2 hybrid gene. Cases 1 and 2 were treated within 1 month and case 3 at 8 months. All the patients showed improved motor function scores and did not require respiratory support. The identification of infants with SMA via NBS and early treatment improved their motor and respiratory outcomes. Thus, implementation of SMA-NBS at a nationwide scale should be considered.

A Case with Iron Deficiency Anemia Developed Aplastic Crisis.

A toddler with an unbalanced diet and gastrointestinal bleeding by juvenile polyp developed an aplastic crisis due to the human parvovirus B19 (HPVB19). Although he exhibited microcytic anemia without iron deficiency in the acute phase of HPVB19 infection, he presented with iron deficiency anemia (IDA) in the chronic phase. IDA results in erythroblast hyperplasia and shortened red blood cell lifespan as like congenital hemolytic diseases, which may lead to an aplastic crisis during HPVB19 infection. It should be noted that iron deficiency is often masked, and microcytic anemia may be a clue for IDA.