The basic information and clinical data of 4 Phelan-McDermid syndrome (PMS) patients in the Pediatric Outpatient Department of the Peking University First Hospital from January 2014 to October 2019 were retrospectively analyzed.Genetic diagnoses were performed using the whole exon sequencing assay.The genotype-phenotype correlation analysis was then performed.All patients presented with intellectual disability/developmental delay, especially the most-common manifestation in language disability.Patient 2 had an autism behavior.Four novel variations of the SHANK3 gene were found in this study, including the c. 2861delC p. (S955Pfs*109), c.3166delC p. (A1039Afs*39), c.3711_3723delGCCCAGCCCCCGG p. (L1241Lfs*29) and c. 2223+ 1G>A.All of them were analyzed as new pathogenic variations according to the American College of Medical Genetics and Genomics criteria.The present study expan-ded the mutant spectrum of the SHANK3 gene, which provided a basis for further accurate genetic counseling and prenatal diagnosis of PMS.

A 6-year-old girl presented with recurrent skin rash at the initial stage, recent joint pain, and neutrophilia was found during a routine blood test. After a multidisciplinary case discussion, she was diagnosed with chronic neutrophil leukemia, and the symptoms were relieved after hydroxyurea and luxolitinib treatment. She received the allogeneic hematopoietic stem cell transplantation subsequently. At present, she is in stable condition and under follow-up. Chronic neutrophil leukemia is a rare disease, which rarely occurs in children. It is more difficult to diagnose in patients with skin rash as the first manifestation. The diagnosis and treatment of this case reflects the important role of multidisciplinary cooperation in the diagnosis and treatment of difficult and rare diseases.