Central precocious puberty in a 3 year-old girl with Phenylketonuria: a rare association?
BACKGROUND
Central precocious puberty (CPP) and phenylketonuria (PKU) are two rare conditions, the latter being the rarer. To date, only one case featuring both these conditions has been reported, and hyperphenylalaninemia was assumed triggering CPP.


METHODS
We present a 3.2 years old girl referred with a 12 months history of breast and pubic hair development, and vaginal discharge. Hyperphenylalaninemia had been identified by newborn screening and PKU subsequently confirmed by plasma amino acid and genetic analysis. Early dietary control of plasma phenylalanine had been excellent afterwards, resulting in phenylalanine concentrations consistently within the recommended range. Clinical scenario, hormonal assessment and imaging were in keeping with true idiopathic central precocious puberty. Treatment with long lasting gonadotropin-releasing hormone analogue led to regression of secondary sexual characteristics.


CONCLUSIONS
We describe for the first time CPP in a girl affected with PKU but with persistently well controlled blood phenylalanine concentrations. This finding is in contrast to a previous report which suggested persistently high phenylalaninemia levels as potential trigger for CPP in PKU patients. Our report, together with the lack of evidence in published cohort studies of children with PKU, strongly suggests this rare association is coincidental and independent of the presence of severe hyperphenylalaninemia.
Laura
L
Lucaccioni
Bernd C
BC
Schwahn
Malcolm
M
Donaldson
Paediatric Endocrinology Unit, Royal Hospital for Sick Children, Dalnair St, Yorkhill, G3 8SJ Glasgow, UK. dr.giacomozzi@gmail.com.
Claudio
C
Giacomozzi
D002675:Child, Preschool; D005260:Female; D006801:Humans; D010649:Phenylalanine / Q000378:metabolism; D010661:Phenylketonurias / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D011379:Prognosis; D011629:Puberty, Precocious / Q000150:complications* / Q000473:pathology
D010649:Phenylalanine