A novel homozygous mutation of the IGFALS gene in a female adolescent: indirect evidence for a contributing role of the circulating IGF-I pool in the pubertal growth spurt.

BACKGROUND

Mutations of the IGFALS gene have been reported since 2004 in 24 patients, but only 5 of these are females.

CASE REPORT: We describe a 14.7-year-old female of a consanguineous Moroccan family with growth retardation and normal-onset but slow progression of puberty without manifest pubertal height gain.

RESULTS

At age 3.2 years, the patient's height was 85.5 cm (-2.9 SDS) and her weight 9.9 kg (-2.9 SDS) with a head circumference of 44.5 cm (-3.3 SDS). Serum IGF-I and IGFBP-3 concentrations were low with normal basal and stimulated growth hormone (GH) levels. An IGF-I generation test confirmed a lack of response to GH administration. While onset of puberty occurred at a normal age, no significant pubertal growth acceleration was observed despite progression of breast development. Sequencing of the IGFALS gene revealed a novel homozygous frameshift mutation (c.1291delT) with a stop codon (p.W431GfsX10) leading to undetectable serum levels of acid-labile subunit.

CONCLUSION

We report the phenotype of an adolescent girl with primary IGF-I deficiency due to a novel homozygous mutation of the IGFALS gene, who presented with growth delay, normal pubertal onset with slow progression and no pubertal growth acceleration indirectly suggesting a contributing role of the circulating IGF-I pool in the pubertal growth spurt.