Aromatic L-aminoacid decarboxylase (AADC) deficiency.
Incidence
Very rare condition.
Clinical Characteristics
This condition has been described only in infancy. It is characterized by oculogyric crisis, hypotonia, sweating, mental retardation, temperature instability, chorea and ptosis of eyelids. All the routine laboratory exams are normal. MRI or CT scan shows cerebral atrophy. Norepinephrine and epinephrine in plasma are decreased. L-dopa is increased in plasma, urine and CSF. 3-O-methyldopa (3OMD) in plasma, urine and CSF is very elevated. 5-hydroxythryptophan (5HTP) in plasma, urine and CSF is elevated. Blood serotonin level are moderate to severely decreased. Plasma L-dopa decarboxylase is very decreased. Homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5 HIAA) in CSF are very decreased. Vanillactic acid (in the urine's organic acid evaluation) is elevated. Phenylalanine levels in plasma is normal. Symptoms present in infancy are oculogyric crisis, ptosis, miosis, and reverse Argyll-Robertson pupil. CNS symptoms include chorea, irritability, mental retardation, and developmental delay, hypotonia. The temperature is unstable and patients show pallor with excessive sweating. Treatment: Monoamine oxidase (MAO) inhibitors in conjunction with dopamine agonists and vitamin B6 (cofactor for AADC) ameliorate symptoms in AADC deficiency.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
All the routine laboratory exams are normal. Plasma L-dopa decarboxylase is very decreased. Norepinephrine and epinephrine in plasma are decreased. L-dopa is increased in plasma, urine and CSF. 3-O-methyldopa (3OMD) in plasma, urine and CSF is very elevated. 5-hydroxythryptophan (5HTP) in plasma, urine and CSF is elevated. Blood serotonin level are moderate to severely decreased. Homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5 HIAA) in CSF are very decreased. Vanillactic acid (in the urine's organic acid evaluation) is elevated.