Clinical and genetic characteristics of Keishi-Bukuryo-Gan syndrome: an analysis of 5 cases.

: To analyze the clinical and genetic characteristics of children with Keishi-Bukuryo-Gan (KBG) syndrome. The clinical and genetic data of 5 children with KBG syndrome admitted in Children's Hospital Affiliated of Zhengzhou University from November 2018 to September 2020 were retrospectively analyzed. Five children were all males who came from four different families. All children presented triangular face, bushy eyebrows, thin upper lip, large or delayed closure of anterior fontanel, and abnormal bone development. Four cases had growth retardation, large ears, thick ear lips; 3 cases had large central incisors; 2 cases had congenital heart disease; 2 cases had abnormal skin changes; 2 cases had genital changes; and 2 cases became grumpy. Liver and kidney function,thyroid function, blood gas analysis and electrolyte of the children were all in the normal range. Three children received bone age examination, and all showed bone age lag. Two cases showed backward myelination of white matter in MRI. Whole exome sequencing revealed that all 5 children had heterozygous mutations in the gene, among which c.6836_6837delTG, c.5866C>T, and c.6270delT were newly discovered mutation sites. None of the parents of probands were found to carry the mutations in gene. Two cases achieved height catch-up and cognitive improvement after treatment with recombinant human growth hormone. KBG syndrome is characterized by a wide spectrum of phenotypes, and large or delayed closure of the anterior fontanel, large ears and thick ear lips may be the main manifestations of the disease in infants and young children. gene mostly presents spontaneous mutations, and early application of growth hormone therapy can achieve height catch-up and cognitive improvement without obvious adverse reactions.