LY Siu, L Kwong, SN Wong, NS Kwong

Abstract

We present the first Chinese case of D-bifunctional protein (DBP) deficiency, a single peroxisomal protein disorder. A non-dysmorphic, 2.53 kg hypotonic female infant developed seizure at fifty-six hours. After seizure onset, she lost her sucking and deep tendon reflex. On day 10, brain stem auditory evoked potential (BAEP) and visual evoked potential (VEP) studies showed marked impairment. Plasma amino acid, serum acylcarnitine pattern and urine organic acid analysis were normal. For persistent seizures, therapeutic trial of pyridoxine, biotin and folinic acid had no effect. Cerebrospinal fluid (CSF) glycine level and urine sulphite screen by Dipstick were normal. At eighth weeks of life, the markedly elevated level of very long chain fatty acid (VLCFA) level was identified. Subsequent biochemical tests revealed pattern consistent with peroxisomal DBP deficiency. Awareness of the suggestive clinical features and loopholes in the routine metabolic screening tests will facilitate early detection of this rare disorder.