Determinants of Plasma Docosahexaenoic Acid Levels and Their Relationship to Neurological and Cognitive Functions in PKU Patients: A Double Blind Randomized Supplementation Study.

Children with phenylketonuria (PKU) follow a protein restricted diet with negligible amounts of docosahexaenoic acid (DHA). Low DHA intakes might explain subtle neurological deficits in PKU. We studied whether a DHA supply modified plasma DHA and neurological and intellectual functioning in PKU. In a double-blind multicentric trial, 109 PKU patients were randomized to DHA doses from 0 to 7 mg/kg&day for six months. Before and after supplementation, we determined plasma fatty acid concentrations, latencies of visually evoked potentials, fine and gross motor behavior, and IQ. Fatty acid desaturase genotypes were also determined. DHA supplementation increased plasma glycerophospholipid DHA proportional to dose by 0.4% DHA per 1 mg intake/kg bodyweight. Functional outcomes were not associated with DHA status before and after intervention and remained unchanged by supplementation. Genotypes were associated with plasma arachidonic acid levels and, if considered together with the levels of the precursor alpha-linolenic acid, also with DHA. Functional outcomes and supplementation effects were not significantly associated with genotype. DHA intakes up to 7 mg/kg did not improve neurological functions in PKU children. Nervous tissues may be less prone to low DHA levels after infancy, or higher doses might be required to impact neurological functions. In situations of minimal dietary DHA, endogenous synthesis of DHA from alpha-linolenic acid could relevantly contribute to DHA status.

NAXE Mutations Disrupt the Cellular NAD(P)HX Repair System and Cause a Lethal Neurometabolic Disorder of Early Childhood.

To safeguard the cell from the accumulation of potentially harmful metabolic intermediates, specific repair mechanisms have evolved. APOA1BP, now renamed NAXE, encodes an epimerase essential in the cellular metabolite repair for NADHX and NADPHX. The enzyme catalyzes the epimerization of NAD(P)HX, thereby avoiding the accumulation of toxic metabolites. The clinical importance of the NAD(P)HX repair system has been unknown. Exome sequencing revealed pathogenic biallelic mutations in NAXE in children from four families with (sub-) acute-onset ataxia, cerebellar edema, spinal myelopathy, and skin lesions. Lactate was elevated in cerebrospinal fluid of all affected individuals. Disease onset was during the second year of life and clinical signs as well as episodes of deterioration were triggered by febrile infections. Disease course was rapidly progressive, leading to coma, global brain atrophy, and finally to death in all affected individuals. NAXE levels were undetectable in fibroblasts from affected individuals of two families. In these fibroblasts we measured highly elevated concentrations of the toxic metabolite cyclic-NADHX, confirming a deficiency of the mitochondrial NAD(P)HX repair system. Finally, NAD or nicotinic acid (vitamin B3) supplementation might have therapeutic implications for this fatal disorder.

Long-term follow-up in patients with CCFDN syndrome.

OBJECTIVE: We describe the 10-year follow-up in a cohort of 16 patients with genetically confirmed congenital cataracts, facial dysmorphism, and neuropathy (CCFDN) syndrome, providing new insights in the clinical course of the disease. METHODS: We performed a detailed clinical and paraclinical characterization and 10-year follow-up study in 16 patients with molecularly defined CCFDN syndrome, illustrating that CCFDN is a severe disabling disorder. RESULTS: All patients initially presented with congenital cataracts along with strabismus, facial dysmorphism, short stature, and demyelinating neuropathy. In all patients, paresis of small hand muscles and foot extensors worsened with disease progression, while ataxia scores remained stable or improved. Nerve conduction velocity was normal in early infancy up to 18 months, decreased to approximately 20 m/s around age 10 years, and then remained stable; distal motor latency was prolonged. Sensory nerve conduction velocities were slowed, and initially of normal amplitude. With disease progression, both sensory and motor nerves showed reduction of amplitudes indicating axonal loss. In 6 patients, acute severe proximal weakness and myalgia after febrile infections, along with rhabdomyolysis, myoglobinuria, and hyperCKemia, led to a less favorable outcome and permanent loss of ambulation in 3 patients. CONCLUSIONS: CCFDN should be classified as a recessive demyelinating sensory-motor neuropathy, and axonal loss is a major determinant of long-term outcomes and disability. Patients benefit from early and ongoing physiotherapy, and should be thoroughly counseled regarding virus-triggered rhabdomyolysis and the risk of malignant hyperthermia. Whether supplementation with liposoluble vitamins results in a therapeutic benefit should be evaluated in further studies.

Are evoked potentials in patients with adult-onset pompe disease indicative of clinically relevant central nervous system involvement?

PURPOSE: Pompe disease is a multisystem autosomal recessive glycogen storage disease. Autoptic findings in patients with classic infantile and late-onset Pompe disease have proven that accumulation of glycogen can also be found in the peripheral and central nervous system. To assess the functional role of these pathologic findings, multimodal sensory evoked potentials were analyzed. METHODS: Serial recordings for brainstem auditory, visual, and somatosensory evoked potentials of 11 late-onset Pompe patients were reviewed. Data at the onset of the enzyme replacement therapy with alglucosidase alfa were compared with follow-up recordings at 12 and 24 months. RESULTS: Brainstem auditory evoked potentials showed a delayed peak I in 1/10 patients and an increased I-III and I-V interpeak latency in 1/10 patients, respectively. The III-V interpeak latencies were in the normal range. Visual evoked potentials were completely normal. Median somatosensory evoked potentials showed an extended interpeak latency in 3/9 patients. Wilcoxon tests comparing age-matched subgroups found significant differences in brainstem auditory evoked potentials and visual evoked potentials. CONCLUSIONS: We found that the majority of recordings for evoked potentials were within the ranges for standard values, therefore reflecting the lack of clinically relevant central nervous system involvement. Regular surveillance by means of evoked potentials does not seem to be appropriate in late-onset Pompe patients.

Does dietary DHA improve neural function in children? Observations in phenylketonuria.

Children with phenylketonuria (PKU) have a restricted protein intake and thus low dietary intakes of long-chain polyunsaturated fatty acids (LC-PUFA), which may cause subtle neurological deficits. We measured plasma phospholipid fatty acids and visual evoked potential (VEP) in 36 children with well-controlled PKU (6.3+/-0.6 years, 19 girls), before and after 3 months of supplementing fish oil capsules providing 15 mg docosahexaenoic acid (DHA)/kg daily. The motometric Rostock-Oseretzky Scale (ROS) was performed before and after supplementation in the 24 PKU children aged >4 years. VEP latencies and ROS were also assessed in omnivorous, age-matched controls without fish oil supply at baseline and after 3 months. Fish oil supply increased plasma phospholipid eicosapentaenoic acid (EPA) (0.40+/-0.03 vs 3.31+/-0.19%, p<0.001) and DHA (2.37+/-0.10 vs 7.05+/-0.24%, p<0.001), but decreased arachidonic acid (AA) (9.26+/-0.23 vs 6.76+/-0.16%, p<0.001). Plasma phenylalanine was unchanged. VEP latencies and ROS results significantly improved after fish oil in PKU children, but remained unchanged in controls. The improvements of VEP latencies, fine motor and coordination skills indicate that preformed n-3 LC-PUFA are needed for neural normalcy in PKU children. The optimal type and dose of supply still needs to be determined. Since PKU children are generally healthy and have normal energy and fatty acid metabolism, these data lead us to conclude that childhood populations in general require preformed n-3 LC-PUFA to achieve optimal neurological function.

Myofascial trigger points in children with tension-type headache: a new diagnostic and therapeutic option.

The goal of this pilot study was to evaluate the effect of a trigger point-specific physiotherapy on headache frequency, intensity, and duration in children with episodic or chronic tension-type headache. Patients were recruited from the special headache outpatient clinic. A total of 9 girls (mean age 13.1 years; range, 5-15 years) with the diagnosis of tension-type headache participated in the pilot study from May to September 2006 and received trigger point-specific physiotherapy twice a week by a trained physiotherapist. After an average number of 6.5 therapeutic sessions, the headache frequency had been reduced by 67.7%, intensity by 74.3%, and duration by 77.3%. No side effects were noted during the treatment. These preliminary findings suggest a role for active trigger points in children with tension-type headache. Trigger point-specific physiotherapy seems to be an effective therapy in these children. Further prospective and controlled studies in a larger cohort are warranted.