Abstract The patient is a male neonate born at term. He was admitted 16 minutes after birth due to stridor and inspiratory respiratory distress. Physical examination revealed a cleft palate, and a grade II systolic ejection murmur was audible at the left sternal border. Whole exome sequencing identified a heterozygous variant in the SON gene, c.5753-5756del (p.Val1918GlufsTer87), which was absent in either parent, indicating a de novo mutation. According to the guidelines of the American College of Medical Genetics and Genomics, this was classified as a "pathogenic variant" leading to a diagnosis of Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome. Upon admission, symptomatic supportive treatment was provided. Follow-up at the age of 8 months revealed persistent stridor; the infant could only consume small amounts of milk and was unable to sit steadily. This patient represents the youngest reported case to date, and his symptoms expand the clinical spectrum of the disease, providing valuable insights for clinical diagnosis and treatment.
Richards S, Aziz N, Bale S, et al. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology[J]. Genet Med, 2015, 17(5): 405-424. PMID: 25741868. PMCID: PMC4544753. DOI: 10.1038/gim.2015.30.
Slezak R, Smigiel R, Rydzanicz M, et al. Phenotypic expansion in Zhu-Tokita-Takenouchi-Kim syndrome caused by de novo variants in the SON gene[J]. Mol Genet Genomic Med, 2020, 8(10): e1432. PMID: 32705777. PMCID: PMC7549597. DOI: 10.1002/mgg3.1432.
Stark Z, Tan TY, Chong B, et al. A prospective evaluation of whole-exome sequencing as a first-tier molecular test in infants with suspected monogenic disorders[J]. Genet Med, 2016, 18(11): 1090-1096. PMID: 26938784. DOI: 10.1038/gim.2016.1.
Kim JH, Shinde DN, Reijnders MRF, et al. De novo mutations in SON disrupt RNA splicing of genes essential for brain development and metabolism, causing an intellectual-disability syndrome[J]. Am J Hum Genet, 2016, 99(3): 711-719. PMID: 27545680. PMCID: PMC5011044. DOI: 10.1016/j.ajhg.2016.06.029.
Quintana Castanedo L, Sánchez Orta A, Maseda Pedrero R, et al. Skin and nails abnormalities in a patient with ZTTK syndrome and a de novo mutation in SON[J]. Pediatr Dermatol, 2020, 37(3): 517-519. PMID: 32045494. DOI: 10.1111/pde.14113.
Takenouchi T, Miura K, Uehara T, et al. Establishing SON in 21q22.11 as a cause a new syndromic form of intellectual disability: possible contribution to Braddock-Carey syndrome phenotype[J]. Am J Med Genet A, 2016, 170(10): 2587-2590. PMID: 27256762. DOI: 10.1002/ajmg.a.37761.
Pasca L, Politano D, Cavallini A, et al. A novel de novo heterozygous mutation in the SON gene associated with septo-optic dysplasia: a new phenotype[J]. Neuropediatrics, 2024, 55(3): 191-195. PMID: 37343586. DOI: 10.1055/a-2114-4387.
Tang S, You J, Liu L, et al. Expanding the mutational spectrum of ZTTK syndrome: a de novo variant with global developmental delay and malnutrition in a Chinese patient[J]. Mol Genet Genomic Med, 2023, 11(8): e2188. PMID: 37488749. PMCID: PMC10422072. DOI: 10.1002/mgg3.2188.
Yi Z, Song Z, Li F, et al. A novel de novo frameshift variation in the SON gene causing severe global developmental delay and seizures in a Chinese female[J]. Int J Dev Neurosci, 2022, 82(3): 271-276. PMID: 35080253. DOI: 10.1002/jdn.10170.
Pietrobattista A, Della Volpe L, Francalanci P, et al. The expanding phenotype of ZTTK syndrome due to the heterozygous variant of SON gene focusing on liver involvement: patient report and literature review[J]. Genes (Basel), 2023, 14(3): 739. PMID: 36981010. PMCID: PMC10048019. DOI: 10.3390/genes14030739.
Pavone P, Saia F, Pappalardo X, et al. Novel malformations: Chiari type 1 and hydrocephalus in Zhu-Tokita-Takenouchi-Kim syndrome and novel SON variants[J]. Clin Case Rep, 2022, 10(12): e6529. PMID: 36540882. PMCID: PMC9755635. DOI: 10.1002/ccr3.6529.
Eid M, Bhatia S. Novel de novo heterozygous variants in the SON gene causing ZTTK syndrome: a case report of two patients and review of neurological findings[J]. Child Neurol Open, 2022, 9: 2329048X221119658. PMID: 36387043. PMCID: PMC9661544. DOI: 10.1177/2329048X221119658.
Van Stechelman P, Wilson B, Grebe TA, et al. Hypogammaglobulinemia in 2 children with Zhu-Tokita-Takenouchi-Kim syndrome[J]. Ann Allergy Asthma Immunol, 2024, 133(1): 109-110. PMID: 38588913. DOI: 10.1016/j.anai.2024.04.005.
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