NDE1-related disorders: A recurrent NDE1 pathogenic variant causing Lissencephaly 4 can also be associated with microhydranencephaly.

NudE Neurodevelopment Protein 1 (NDE1) gene encodes a protein required for microtubule organization, mitosis, and neuronal migration. Biallelic pathogenic variants of NDE1 gene are associated with structural central nervous system abnormalities, specifically microlissencephaly and microhydranencephaly. The root of these different phenotypes remains unclear. Here, we report a 20-year-old male patient referred to our clinics due to severe microcephaly, developmental delay, spastic quadriplegia, and dysmorphic features. The cranial computed tomography revealed abnormal brain structure and excess of cerebrospinal fluid, consistent with microhydranencephaly. A homozygous c.684_685del, p.(Pro229TrpfsTer85) change in NDE1 gene was found by clinical exome analysis. The variant has previously been reported in individuals with microlissencephaly, therefore we propose that the same variant within the gene may cause either microlissencephaly or microhydranencephaly phenotypes. There are only a few papers about NDE1-related disorders in the literature and the patient we described is important to clarify the phenotypic spectrum of the disease.