Exome Sequencing Identifies Multiple Genetic Diagnoses in Children with Syndromic Growth Disorders

Abstract

To evaluate the presence of multiple genetic diagnoses in syndromic growth disorders. We carried out a cross-sectional study to evaluate 115 patients with syndromic tall (n=24) or short stature (n=91) of unknown cause from a tertiary referral center for growth disorders. Exome sequencing was performed to assess germline single nucleotide, InDel, and copy number variants. All variants were classified according to ACMG/AMP guidelines. The main outcome measured was the frequency of multiple genetic diagnoses in a cohort of children with syndromic growth disorders. The total diagnostic yield of the cohort was 54.8% (63/115). Six patients had multiple genetic diagnoses (tall stature group=2; short stature group=4). The proportion of multiple diagnoses within total cases was 5.2% (6/115), and within solved cases was 9.5% (6/63). No characteristics were significantly more frequent when compared with patients with single or multiple genetic findings. Among patients with multiple diagnoses, 3 had syndromes with overlapping clinical features, and the others had syndromes with distinct phenotypes. Recognition of multiple genetic diagnoses as a possibility in complex cases of syndromic growth disorders opens a new perspective on treatment and genetic counseling for affected patients, defying the medical common sense of trying to fit all findings into one diagnosis.