Severe Hypoplasia/Aplasia of the Medullary Arcuate Nucleus in a 4-Month-Old Patient with Sudden Infant Death Syndrome

Abstract

The aim of this study was to verify and confirm the close correlation between the absence of the medullary arcuate nucleus and sudden death in a 4-month-old infant. Careful neuropathological examination of the cerebral hemispheres, basal ganglia, and cerebellum demonstrated no relevance to the death. The brainstem region, normally occupied by the nuclei, was cut into several serial sections so as not to lose any details. The largest median part of the medullary arcuate nucleus was completely absent, and only very small groups of residual neurons in its most lateral part were still detectable; the rest of the brainstem showed no abnormalities. In the absence of other lesional, degenerative, or malformative causes, the sudden and unexpected death of this infant was likely due to severe hypoplasia/aplasia of the medullary arcuate nucleus. The anatomo-functional development of the nucleus and its crucial role in the control of respiratory and cardiac autonomic reactivity in sleep during the first year of life may provide an important contribution to the pathogenic interpretation.

Keywords

ARCn - autonomic nervous system - hypoplasia/aplasia - medullary arcuate nucleus - SIDS

Ethical Statement

The study did not need the approval of the Ethical Committee of our University Administration, as it is not required for the publication of a single case of particular interest to the scientific community (Regulations of the Ethical Committee of Area Vasta Emilia Nord, Italy, approved on September 22, 2020).

Patient Consent

The informed consent has been obtained and the patient's anonymity has been preserved.

Authors' Contributions

Conceptualization: E.D.G., T.S., L.R.B. Data curation: E.D.G., T.S., L.R.B., L.M. Writing-original draft preparation: E.D.G., T.S., L.F. Writing-review and editing: E.D.G., T.S., L.R.B., A.M. All authors have read and agreed to the published version of the manuscript.

Publication History

Received: 27 September 2023

Accepted: 01 June 2024

Article published online:
04 July 2024

• References

• 1 Filiano JJ, Kinney HC. A perspective on neuropathologic findings in victims of the sudden infant death syndrome: the triple-risk model. Biol Neonate 1994; 65 (3-4): 194-197
• 2 Filiano JJ, Kinney HC. Arcuate nucleus hypoplasia in the sudden infant death syndrome. J Neuropathol Exp Neurol 1992; 51 (04) 394-403
• 3 Filiano JJ. Arcuate nucleus hypoplasia in sudden infant death syndrome: a review. Biol Neonate 1994; 65 (3-4): 156-159
• 4 Matturri L, Biondo B, Mercurio P, Rossi L. Severe hypoplasia of medullary arcuate nucleus: quantitative analysis in sudden infant death syndrome. Acta Neuropathol 2000; 99 (04) 371-375
• 5 Matturri L, Biondo B, Suárez-Mier MP, Rossi L. Brain stem lesions in the sudden infant death syndrome: variability in the hypoplasia of the arcuate nucleus. Acta Neuropathol 2002; 104 (01) 12-20
• 6 Matturri L, Ottaviani G, Alfonsi G, Crippa M, Rossi L, Lavezzi AM. Study of the brainstem, particularly the arcuate nucleus, in sudden infant death syndrome (SIDS) and sudden intrauterine unexplained death (SIUD). Am J Forensic Med Pathol 2004; 25 (01) 44-48
• 7 Biondo B, Lavezzi A, Tosi D, Turconi P, Matturri L. Delayed neuronal maturation of the medullary arcuate nucleus in sudden infant death syndrome. Acta Neuropathol 2003; 106 (06) 545-551
• 8 Kerbl R, Zotter H, Einspieler C. et al; Styrian Sudden Infant Death Study Group. Classification of sudden infant death (SID) cases in a multidisciplinary setting. Ten years experience in Styria (Austria). Wien Klin Wochenschr 2003; 115 (24) 887-893
• 9 Krous HF, Beckwith JB, Byard RW. et al. Sudden infant death syndrome and unclassified sudden infant deaths: a definitional and diagnostic approach. Pediatrics 2004; 114 (01) 234-238
• 10 Zec N, Filiano JJ, Kinney HC. Anatomic relationships of the human arcuate nucleus of the medulla: a DiI-labeling study. J Neuropathol Exp Neurol 1997; 56 (05) 509-522
• 11 Yamaguchi K, Yazawa T. Development of the human medullary arcuate nucleus from mid-gestation to the perinatal period: a morphometric study. Neurosci Lett 2024; 818: 137537
• 12 Paradiso B, Ferrero S, Thiene G, Lavezzi AM. Variability of the medullary arcuate nucleus in humans. Brain Behav 2018; 8 (11) e01133
• 13 Baizer JS, Webster CJ, Witelson SF. Individual variability in the size and organization of the human arcuate nucleus of the medulla. Brain Struct Funct 2022; 227 (01) 159-176