The central nervous system in microcephalic primordial dwarfism: Is there a characteristic developmental brain pathology in Seckel or Seckel-like syndrome?

Abstract

In spite of the description of more than 70 cases of Seckel syndrome (SS) or Seckel-like primordial microcephalic dwarfism, reports about investigations into the central nervous system pathology in SS remaind infrequent Here we comment on the thorough neuropathological examination of the brain in a familial case of Seckel-like microcephalic dwarfism. The male fetus of a 6 gravida, 3 para was aborted at 19 weeks of gestation after prenatal ultrasound examination with the demonstration of severe microcephaly and retarded intrauterine development The propositus had two healthy sisters. Of two aborted fetuses and one deceased sibling, the deceased had also exhibited a Seckel-like phenotype as well as, in MRI scans, micrencephaly, callosal agenesis and pachygyria. Neuropathological examination of the brain in the propositus resulted in the demonstration of two main categories of changes: (1) defective telencephalic midline structures (arhinencephaly as well as callosal, septal, fornical, and hippocampal agenesis), and (2) impairment of migration (micrencephaly with lack of cortical neuroblasts in both the telencephalon and the rhombencephalon as well as heterotopias in the former). These findings corresponded with those described in the few neuropathological and neuroradiological literature reports, indicating that there appears to be in SS-like primordial microcephalic dwarfism and a characteristic, although not specific brain pathology which might be adequately summarized by the designation mediodysgenetic micrencephaly. The genetic background of SS as a basis for the CNS maldevelopment is discussed.