A SOX3 (Xq26.3-27.3) duplication in a boy with growth hormone deficiency, ocular dyspraxia, and intellectual disability: a long-term follow-up and literature review

Abstract

Objective: SOX3 is located on the long arm of the X chromosome (Xq27.1) and both the under- and over-expression of this gene have been reported in cases of hypopituitarism with or without intellectual disabilities. Nevertheless, only a few cases have as yet been extensively described.

Design: A 3-year 11 month-old male was brought in for growth failure (height -2.4 SDS). The patient was born at term of a second uneventful pregnancy by caesarean section for podalic presentation: the birth weight (0.1 SDS), length (0.4 SDS), and head circumference (-0.3SDS) were normal. Neurodevelopmental delays and ocular motor dyspraxia had been noted since 6 months of age. The endocrinological evaluation showed a very low IGF-I concentration (44 μg/L). The thyroid hormone level was normal and coeliac disease markers were negative. Bone age was considerably delayed. Target height was normal (0.5 SDS).

Results: Growth hormone stimulation tests were compatible with a classic GHD, while a brain MRI disclosed a pituitary hypoplasia with ectopic neurohypophysis. rhGH treatment was then begun and the auxological follow-up showed a good response. At the age of 9 yrs, the height was 0.3 SDS, the weight was 0.1 SDS, and the pubertal evaluation was PH1 AH1 T2 ml bilaterally. Due to the presence of neuromotor delays and MRI abnormalities, a genetic evaluation was conducted and an array-CGH of the patient's DNA discovered an Xq26.3-27.3 duplication comprising the SOX3 gene.

Conclusions: SOX3 involvement should be considered in a male with short stature due to GH deficiency associated with intellectual disability.