Sight-threatening phenylketonuric encephalopathy in a young adult, reversed by diet.

S. Rubin, A. L. Le Piffer, M. B. Rougier, M. N. Delyfer, J. F. Korobelnik, I. Redonnet-Vernhet, C. Marchal, C. Goizet, S. Mesli, C. Gonzalez, H. Gin, V. Rigalleau
JIMD Reports. 2012-01-01; : 83-85
DOI: 10.1007/8904_2012_207

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1. JIMD Rep. 2013;10:83-5. doi: 10.1007/8904_2012_207. Epub 2013 Feb 12.

Sight-threatening phenylketonuric encephalopathy in a young adult, reversed by

Rubin S(1), Piffer AL, Rougier MB, Delyfer MN, Korobelnik JF, Redonnet-Vernhet I,
Marchal C, Goizet C, Mesli S, Gonzalez C, Gin H, Rigalleau V.

Author information:
(1)Service de Nutrition, CHU de Bordeaux, Avenue de Magellan, 33604, Pessac,
France, .

Phenylketonuria (PKU) leads to severe neurological disorders in childhood,
shunned by the diet. The long-term prognosis after diet diversification at
adolescence is uncertain. We report a case of cortical blindness in a young
patient regressive 1 month after the diet was resumed.Mr M., 25 years old, had
PKU detected at birth. He maintained good serum levels of Phenylalanine (Phe)
(120-300 μmol/L) during childhood and got a normal intellectual development.
During adolescence he diversified his diet but maintained low meat and fish
intake; Phe was ~1,200 μmol/L with no symptoms. In 2009, the patient stopped the
low-Phe amino acid substitutes due to weariness. On June 27, 2011, he consulted
for a decrease of visual acuity progressing for 6 months. Ophthalmologic
examination found that visual acuity was 2/10 in two eyes associated to a central
visual field defect. The visual evoked potentials were altered. MRI showed
bilateral and symmetric occipital FLAIR hyperintensities. On admission in the
Nutrional Unit on June 29, 2011, blood pressure was 120/70 mmHg, there was no
other neurological abnormality. Phe was at 1,512 μmol/L, and not responsive to
BH4. He was then treated with a very low-Phe diet with an amino acid substitute,
and he obtained Phe between 120 and 300 μmol/L. Visual acuity was suddenly
restored on August 1, 2011, with a dramatic attenuation of the MRI
hyperintensities.Our observation shows that the withdrawal of the diet and
substitutes exposes to serious neurological complications in adults that may
reverse with a fast nutritional support.

DOI: 10.1007/8904_2012_207
PMCID: PMC3755574
PMID: 23430807

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