Genetic Manifestations and Phenotype Spectrum in Infants With Feeding Difficulty.

ABSTRACT

BACKGROUND: Feeding difficulties frequently co-occur with multisystem disorders attributed to rare genetic diseases. In this study, we aimed to describe the genetic manifestations and phenotype spectrum in infants experiencing feeding difficulties. METHODS: This case series included infants under 6 months old with feeding difficulties admitted to the neonatal department of Children's Hospital, Zhejiang University School of Medicine from October 2018 to May 2022. All infants underwent whole-exome sequencing (WES) during hospitalisation, and their clinical phenotypes and genetic results were analyzed. RESULTS: Among 28 infants studied, nine were preterm and 19 were full-term. Median admission age was 13.5 days (IQR 6.5, 35), with a median hospital stay of 16 days (IQR 10.5, 30). Overall, 12 (42.9%) cases were complicated with multiple malformations. Abnormal muscle tone (53.6%) and neurological issues (42.9%) were notable prevalent in these infants. Cranial MR abnormalities were noted in 96.2% of cases. Based on the combined analysis of WES results and clinical phenotypes, a total of 22 (78.3%) patients displayed disease-related genetic variation identified through WES; among them, 15 (53.6%) patients received genetic diagnoses, while 7 (25%) patients were suspected diagnoses. Positive findings were more frequent in full-term (89.5%) than preterm infants (55.6%). Ultimately, 24 (85.7%) patients were discharged alive, with 75% requiring post-discharge tube feeding. Following discharge, five patients developed new symptoms linked to genetic variants, and two patients died. CONCLUSIONS: Feeding difficulty may constitute a facet of the phenotypic spectrum of rare genetic diseases. Whole-exome sequencing can enhance molecular diagnosis accuracy for infants with feeding difficulties.