Adult phenylketonuria presenting with subacute severe neurologic symptoms.
We report a 48-year-old Japanese woman with phenylketonuria (PKU) who presented with severe neurological symptoms more than 30 years after discontinuation of dietary treatment. She was diagnosed with PKU at 6-years-old and was treated with a phenylalanine restricted diet until she was 15 years old. When she was 48-years-old she started having difficulty walking. After several months, she presented with severe disturbance of consciousness and was admitted. She was diagnosed as having neurological complications associated with PKU. We observed temporal changes in her laboratory data, brain MRI and single-photon emission computed tomography (SPECT) scan findings. Brain MRI on T2-weighted, fluid-attenuated inversion recovery and diffusion-weighted images revealed high intensity lesions in her bilateral frontal lobes and 123I-IMP SPECT showed marked and diffuse hypoperfusion in the bilateral cerebrum and cerebellum. After the resumption of dietary treatment, serum phenylalanine concentrations immediately decreased to the normal range. However, her neurological symptoms took longer to improve. We also found no clear temporal association between MRI findings and clinical severity. SPECT abnormalities showed marked improvement after treatment. It is well known that PKU patients who discontinue the dietary restriction from their childhood develop minor neurological impairments. However, PKU patients with late-onset severe neurological symptoms are very rare. To our knowledge, this is the first report regarding SPECT findings of PKU patients with late-onset severe neurological deterioration.
Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Electronic address: sekimori709@gmail.com.
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Seki
Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Takizawa
Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Suzuki
Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Shimizu
Department of Pediatrics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Shibata
Department of Pediatrics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Ishii
Department of Pediatrics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Hasegawa
Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Suzuki
D001921:Brain / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D010661:Phenylketonurias / Q000150:complications* / Q000178:diet therapy / Q000473:pathology*; D015899:Tomography, Emission-Computed, Single-Photon
Adult; MRI; Neurological deterioration; Phenylketonuria; SPECT