ESPE Abstracts

Background: Floating-Harbor Syndrome (FHS) is a rare disorder characterized by facial dysmorphism, short stature, and delayed language development, among other clinical manifestations. In this case-cohort study, we aim ed to evaluate the clinical features and treatment outcomes of ten Chinese children diagnosed with FHS treated with recombinant human growth hormone (rhGH) or nutritional therapy.

Methods: In this retrospective study, we extracted the clinical features, height standard deviation score (SDS), genetic characteristics, and treatment outcomes of ten Chinese children from the patient's medical records. The treatment response was classified as poor, moderate, or good according to the changes in SDS and increase in height per year.

Results: All ten patients presented with short stature (SDS ≤ -2) or less at diagnosis, along with distinct facial features and non-specific skeletal abnormalities. All patients experienced significant delays in language expression, feeding difficulties, varying degrees of intellectual disability, and diverse organ abnormalities. Whole Exome Sequencing (WES) revealed that the pathogenic or likely pathogenic variants were located on the 34^th exon and consisted of a total of eight different mutations, including three novel variants (c.7225dupG/p.Ala2409fs, c.7382delC/p.P2461Qfs*14, and c.7255C>T/p.Gln2419Ter). Out of the ten patients, one experienced growth hormone (GH) deficiency, three had undetermined GH status, and six had no GH deficiency. Eight patients were treated with rhGH, of whom six demonstrated a good response, and two exhibited a moderate response. One patient had a contraindication for rhGH treatment and was effectively treated with nutritional therapy.

Conclusions: Although FHS is a relatively rare disorder, its prevalence amongst the Chinese population should not be underestimated. Genetic testing plays a crucial role in the diagnosis of FHS. The rhGH treatment effectively increased the patients' stature. In patients with contraindications for GH treatment, nutritional therapy was also found to be effective in increasing their stature. However, relief of other systemic abnormalities may require multiple gradual interventions.

Keywords: Floating-Harbor Syndrome, Chinese, Short Stature, Children, recombinant human growth hormone, nutritional intervention