Familial Short Stature

Excerpt

Familial short stature (FSS) is a condition in which the final adult height achieved is less than the third percentile for the patient's age, gender, and population. Nevertheless, it is consistent with parental height in the absence of nutritional, hormonal, acquired, genetic, and iatrogenic causes. It is considered one of the most common causes of short stature, along with the constitutional delay in growth and puberty (CDGP), from which it can easily be distinguished.

A child presenting with short stature (SS) two or more standard deviations (SD) below the mean for age, gender, and population where no other causes can be found deemed to have idiopathic short stature (ISS). Having adopted this definition, some authorities have included cases of FSS and CDGP as part of ISS. Hence, a category of familial ISS is distinguished from the non-familial ISS. On the other hand, others have listed it as a separate entity. Regardless of the classification which one follows, it is clear that FSS is a distinct entity whereby patients attain a final adult height consistent with their target height, unlike ISS. Thus, the final height attained is considerably less than the ultimate expected height in ISS.

Although the consensus is that small cumulative effects of multiple genes are responsible for FSS, it is being questioned, especially when the SS condition is extreme. This may be especially true, as more and more monogenic gene defects are discovered in cases diagnosed either as FSS or ISS and other family members. This article addresses the features of FSS and covers distinctions among CDGP, ISS, and other causes of short stature. It also describes the latest advances in the study of various monogenic gene defects discovered in cases of SS, occurring in some families.