Background: IGF1 is the key effector peptide in the control of normal growth. IGF1 deficiency in the presence of normal GH is associated with growth failure. This may be caused by primary defects in the GH-IGF1 axis or by conditions such as malnutrition or chronic inflammation. Severe primary IGF1 deficiency (height <−3 S.D., serum IGF1 <2.5th centile, GH normal) is an European Medicines Agency (EMA) licensed indication for rhIGF1 therapy. We report a patient with severe failure to thrive, short stature and unexplained IGF1 deficiency who showed an excellent response to rhIGF1 therapy.
Case: A 10 month old girl was referred with severe failure to thrive (weight: 4.2 kg, −7.95 S.D.s, length 60.1 cm, −4.40 S.D.s). She was born to non-consanguineous Caucasian parents at 36 weeks gestation weighing 2.85 kg. She was not dysmorphic or micro cephalic, had gross motor delay, no recurrent infections and a very good caloric intake. Russell-Silver syndrome, skeletal dysplasia, malabsorption and chronic illness were excluded. Cranial MRI was normal and IGF1 was persistently undetectable. Further investigations are as follows (see Table 1): GH therapy (37 μg/kg per day) caused severe diarrhoea with no increase in height velocity or IGF1 level. She was treated with rhIGF1, 120 μg/kg twice daily. After 1 years of treatment, height improved from −4.40 to −1.48 S.D.s and weight from −7.95 to −0.94 S.D.s. The serum IGF1 level normalised (20.9 nmol/l) and age-appropriate motor milestones were achieved. Exome sequencing results are awaited.
|Glucagon stimulation||Peak GH level-6.33 μg/l|
|IGF1 generation||IGF1 undetectable (<3.3 nmol/l) after GH (33 μg/kg per day×4). IGFBP3 increased from 0.5 to 1.3 mg/l(0.52.9)|
|GH receptor gene sequencing||Normal|
Conclusions: This child with IGF1 deficiency associated with severe failure to thrive of unknown aetiology has shown excellent linear and developmental response to within-label use of rhIGF1 therapy and continues to benefit from this treatment.
01 Oct 2015 - 03 Oct 2015