CEDNIK syndrome with phenotypic variability.

CEDNIK syndrome is a rare autosomal recessive syndrome characterized by cerebral dysgenesis, neuropathy, ichthyosis, and keratoderma of which 25 cases from 19 families have been reported to date. It is a progressive neurodegenerative disorder caused by the loss-of-function pathogenic variant of the SNAP29 gene encoding a member of the SNARE family of proteins. We describe two female siblings from a Syrian parent-related family with CEDNIK syndrome due to homozygous pathogenic variant in SNAP29 [c.223delG(p.Val75Serf*28)]. Palmoplantar keratoderma, reported as a cardinal sign in CEDNIK syndrome, was absent in both patients as of the last follow-up, and one of our patients had a verrucous venous malformation, a finding that has not been previously reported.

Generation and Characterization of a CRISPR/Cas9-Mediated SNAP29 Knockout in Human Fibroblasts.

Loss-of-function mutations in the synaptosomal-associated protein 29 (SNAP29) lead to the rare autosomal recessive neurocutaneous cerebral dysgenesis, neuropathy, ichthyosis, and keratoderma (CEDNIK) syndrome. SNAP29 is a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein. So far, it has been shown to be involved in membrane fusion, epidermal differentiation, formation of primary cilia, and autophagy. Recently, we reported the successful generation of two mouse models for the human CEDNIK syndrome. The aim of this investigation was the generation of a CRISPR/Cas9-mediated SNAP29 knockout (KO) in an immortalized human cell line to further investigate the role of SNAP29 in cellular homeostasis and signaling in humans independently of animal models. Comparison of different methods of delivery for CRISPR/Cas9 plasmids into the cell revealed that lentiviral transduction is more efficient than transfection methods. Here, we reported to the best of our knowledge the first successful generation of a CRISPR/Cas9-mediated SNAP29 KO in immortalized human MRC5Vi fibroblasts (c.169_196delinsTTCGT) via lentiviral transduction.

Pyloric Stenosis in a Patient with CEDNIK Syndrome.

We present a rare neurocutaneous genetic disorder where patients develop a combination of cerebral dysgenesis, neuropathy, ichthyosis, and keratoderma, commonly known as CEDNIK syndrome. It is an autosomal recessive inheritance involving the SNAP29 protein, mapped to the 22q11.2 gene. Phenotypic variation is seen with this disease, with clinical manifestation of developmental milestone delays ranging in severity. With only a handful of documented cases, available research, management of the syndrome, and prognosis are not well established. As CEDNIK syndrome has systemic implications, care coordination between specialists is essential in improving patient outcomes. Particularly important is preventing patients from meeting the criteria of failure to thrive, a commonly reported issue. In this case, we present a four-month-old male with a past medical history of pyloric stenosis status/post pyloromyotomy who has failure to thrive, gastroesophageal reflux disease, profound hypotonia, and delayed progression of developmental milestones. Additionally, the case is complicated by idiopathic pyloric stenosis, further contributing to the patient's failure to thrive. We aim to discuss the pathophysiology of this syndrome, explore the timeline of disease progression, as well as compare our case to the current literature.

CEDNIK syndrome in a Brazilian patient with compound heterozygous pathogenic variants.

CEDNIK (Cerebral Dysgenesis, Neuropathy, Ichthyosis, and Keratoderma) syndrome is a neuro ichthyotic syndrome characterized by a clinical constellation of features including severe developmental delay, microcephaly, and facial dysmorphism. Here, we report the clinical and molecular characterization of a patient with CEDNIK syndrome harboring two compound heterozygous variants in the SNAP29 gene. The patient presents a combination of a loss-of-function SNAP29 mutation and a ∼370 kb 22q11.2 deletion, each of these genetic variants inherited from one of the parents. This report provides detailed data of a patient with unprecedented genetic events leading to the CEDNIK phenotype and may contribute to the elucidation of this rare condition.

Analysis of clinical phenotype and genotype of cerebral dysgenesis, neuropathy, ichthyosis, and palmoplantar keratoderma syndrome caused by a novel variant of SNAP29 gene / 中华神经科杂志

Objective:To investigate the clinial phenotype and genetic characteristics of a child with cerebral dysgenesis, neuropathy, ichthyosis, and palmoplantar keratoderma (CEDNIK) syndrome and to improve the clinicians′ understanding of this disease.Methods:Clinical data of the child with CEDNIK syndrome diagnosed in Department of Endocrinology, Genetics and Metabolism, Xi′an Children′s Hospital in June 2020 were collected. Whole exome sequencing was carried out to identify the potential variants of SNAP29 gene. Suspected variants were verified by Sanger sequencing of family numbers. The literature about the cases of CEDNIK syndrome were reviewed.Results:The proband is a boy, who was aged 1 year and 4 months, had the manifestations of psychomotor retardation, microcephaly, feeding difficulties, severe malnutrition, recurrent respiratory tract infection, binocular esotropia, sensorineural deafness, cutaneous ichthyosis and keratosis, left cryptorchidism. Brain magnetic resonance imaging indicated congenital dysplasia. Whole exome sequencing identified a homozygous variant of c.383dupT (p.E129Rfs *5) in the SNAP29 gene of the proband, and the heterozygous variation was observed at the same locus in his parents, which conformed to the autosomal recessive inheritance. This mutataion was determined as a pathogenic mutation according to the guidelines of American College of Medical Genetics and Genomics. Literature retrieval showed currently a total of 29 cases of CEDNIK syndrome were reported, containing 8 types of SNAP29 gene mutation. However, there was no Chinese case reported. And the c.383dupT (p.E129Rfs *5) mutation found in this study was a novel one which had not been reported yet. Conclusion:The phenotype of the proband is generally consistent with the CEDNIK syndrome and the novel c.383dupT (p.E129Rfs *5) mutation of SNAP29 gene is the genetic cause.