Definition and prevalence of familial short stature.

Objective: To verify the prevalence of novel definitions of familial short stature on a cross-sectional cohort of children referred for short stature when their height and that of both parents were measured.

Methods: We consecutively enrolled 65 individuals referred for short stature when both parents were present. We defined "target height-related short stature" (TH-SS) when child's height is ≤ - 2 SDS and included in the range of target height; suspected "autosomal dominant short stature" (AD-SS) when child height and at least one parent height are ≤ - 2 SDS; "constitutional familial short stature" (C-FSS) when a child with TH-SS does not have any parents with height ≤ - 2 SDS.

Results: Of 65 children referred for SS, 48 individuals had a height ≤ - 2 SDS. Based on the parents' measured heights, 24 children had TH-SS, 16 subjects AD-SS, and 12 individuals C-FSS. If we had considered only the parents' reported height, 3 of 24 children with TH-SS, 9 of 16 with AD-SS, and 10 of 12 with C-FSS would have been lost.

Conclusion: We suggest novel definitions to adequately detect and approach the cases of FSS since C-FSS (25%) might not need any specific investigation, while on the contrary, AD-SS (33%) should undergo genetic evaluation. Moreover, this study underlines that adequate measurement and consideration of children's and parents' heights (individually and together) are crucial in the clinical evaluation of every child with short stature.