A term born 6-month-old, lethargic blonde infant, presented with multiple episodes of vomiting, poor feeding, convulsions and severe psychomotor retardation. O/E: - Microcephaly with prominent maxillae and widely spaced teeth Blue iris Seborrheic or eczematoid rash Spasticity, hyperreflexia, and tremor Musty odour of urine MRI brain All of the following statements are true about the disease except: -

This is a case of Phenylketonuria. Autosomal recessive Deficiency of Phenylalanine hydroxylase May also be due to deficiency of cofactor tetrahydrobiopterin BH4 Leads to hyperphenylalaninemia - Impairs brain development Normal at bih Becomes symptomatic later on in life Present with seizures, hypopigmentation of skin and hair, mental retardation. Complications can be avoided by restricting phenylalanine intake in diet. Diagnosed by: - Guthrie test Tandem mass spectrometry- measure amino acid Immunoassays MRI image shows affected periventricular/ parieto-occipital white matter (due to hypomyelination). Pegvaliase can be given in adults.