Phenylketonuria: Our Experience in Nine Years at a Tertiary-level Referral Institute

Phenyl ketonuria is an inborn error of amino acid metabolism resulting in excessive phenyl alanine levels in blood resulting in a spectrum of neurological defects.

We retrospectively went through the records of patients diagnosed as Phenyl ketonuria in the last nine years in our team and patients who's data could be accessed were analyzed in detail. Details of laboratory tests, imaging clinical features, course were recorded.

A total of 32 patients were identified in nine years of which data was available only for 15 patients. Age at diagnosis varied from 2.5 years to 7 years. 73% were males. Global developmental delay, Microcephaly. Seizures blond hair, spasticity, regression, Ocular Hypertelorism, low set ears, Seborrhea, Hypotonia, Family history of mental retardation and Consanguinity was common one patient showed a large hypo pigmented area in left arm with eczematous rash.

Urine ferric chloride test and DNPH was positive in all cases. Tandem mass spectroscopy showed elevated phenyl alanine, normal tyrosine and elevated PHE tyrosine ratio in all cases. MRI showed symmetrical Flair hyperintensities in T2 weighted images in the parieto occipital region hypo on T1 with no diffusion restriction in 11 cases and MRS was normal. Genetic testing showed one non consanguineous family having carrier state. Follow up is from 1 year to 5 years. Seizures controlled in all. Regular fallow up shows change in hair color and gain of mile stones. There was no mortality.

Phenyl ketonuria is a controllable metabolic disease. However there is considerable delay before diagnosis resulting in persistence of sequelae in children with PKU as well as normal children born to PKU mothers which needs attention to prevent these complications.