Cytogenetic anomalies are the predominant genetic alteration in children with nonfamilial tall stature: a comparative study with familial cases
摘要
The purpose of this study is to elucidate the genetic causes and phenotypic presentation of nonfamilial tall stature (nFTS) and to compare these findings with those of familial tall stature (FTS) from the same population that was previously studied. Children with nFTS (defined as a height > + 2 SDs with both parents’ heights < + 2 SDs) underwent endocrine and anthropometric examinations and genetic testing (karyotyping, SHOX gene dosage analysis and next-generation sequencing of 786 growth-associated genes). Exome sequencing was performed in patients with negative genetic results and a height > + 3 SDs. A total of 55 children with nFTS were enrolled. The median height was + 2.8 SD (2.4–3.2 SD), and the median midparental height was + 0.7 SD (0.4–0.9 SD). Genetic causes of tall stature were identified in 6/55 (11%) children. Specifically, four children had gonosomal aneuploidy (47,XXY [2x], 47,XXX, 48,XXXX), one had a heterozygous complex rearrangement including SHOX gene duplication, and one carried a pathogenic variant in the TGFBR2 gene leading to Loeys–Dietz syndrome. A genetic cause of tall stature was significantly less common in nFTS (11%) than in our previously published cohort with FTS (32%).
Conclusion: Cytogenetic abnormalities were the predominant genetic alteration identified in children with nFTS, confirming the justification of karyotype analysis in this cohort. The probability of genetic alterations was greater in children with FTS than in those with nFTS. Our findings suggest that the current guidelines for complex investigation are efficient for children with nFTS but need revision in children with FTS.