A position statement on the post gene-therapy rehabilitation of aromatic I-amino acid decarboxylase deficiency patients.

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare genetic disorder of monoamine neurotransmitter synthesis that presents with a range of symptoms, including motor dysfunction and limited attainment of developmental motor milestones. The approval of eladocagene exuparvovec, a gene therapy for AADC deficiency with demonstrated efficacy for motor improvements, now expands the range of motor outcomes possible for patients with this disorder. However, recommendations and guidelines for therapy following treatment with gene therapy are lacking. To ensure patients can reach their full potential following treatment with gene therapy, it is essential they receive rehabilitation therapies designed specifically with their impairments and goals in mind. Therefore, we highlight specific rehabilitative needs of patients following gene therapy and propose a set of recommendations for the post-treatment period based on collective experiences of therapists, physicians, and caregivers treating and caring for patients with AADC deficiency who have been treated with gene therapy. These recommendations include a focus on periods of intensive therapy, facilitating active movements, training for functional abilities, cognitive and communication training, parent/caregiver empowerment, collaboration between therapists and caregivers to develop in-home programs, and the incorporation of supplemental forms of therapy that patients and their families may find more enjoyable and engaging. Many of these rehabilitative strategies may be employed prior to gene therapy. However, these recommendations will be valuable for therapists, caregivers, and wider treatment teams as they prepare for the post-treatment journey with these patients. Furthermore, the considerations and recommendations presented here may prove beneficial outside the AADC deficiency community as gene therapies and other treatments are developed and approved for other rare diseases.

Dietary intake and nutritional status of patients with phenylketonuria in Taiwan.

Phenylalanine hydroxylase (PAH) deficiency leads to phenylalanine accumulation and results in phenylketonuria (PKU). Phenylketonuria can contribute to severe inability such as mental impairment. Early diagnosis and dietary intervention can have beneficial effects on maintaining normal neural and cognitive function in patients with PKU. However, a long-term low phenylalanine diet may put children at risk of malnutrition. A food supplement was therefore used for children with PKU under dietician supervision according to dietary reference intakes (DRIs). In this cross-sectional study, we enrolled patients with PKU and age-matched controls to compare their anthropometry data [weight, height, body mass index (BMI), and body composition using bioelectrical impedance analysis (BIA)], and correlated it with their dietary intake based on 24-h dietary recall. For continuous parameters, the data were expressed as median ± standard deviation (SD), and the Mann-Whitney U test was used to test the difference among the groups. Correlation by natural proteins, body fat, and fat-free mass were evaluated using the Pearson correlation coefficient. Twenty-two participants diagnosed with PKU (ages 8-27 years; mean 15.23 ± 5.23) and a control group of 22 non-PKU participants (ages 8-39 years; mean 19.73 ± 10.6) were recruited for this study. Between the two groups of participants, no significant difference was found in height, weight, BMI, muscle mass, or fat mass. The percentage of natural protein has no effect on body composition. We found a significant positive correlation between the total protein intake percentage of DRIs and muscle mass (r = 0.491, p = 0.020) and a significant negative correlation in the total protein intake percentage of DRIs and fat mass (r = -0.475, p = 0.025) in participants with PKU. There were no significant differences in body composition and nutrition intake between patients with PKU (under metabolic control) and healthy subjects. Thus, giving proper nutrition treatment may have beneficial effects on body growth and nutrition status in patients with PKU in Taiwan.

Integrated care for Down syndrome.

Down syndrome (DS), caused by an extra copy of chromosome 21 (trisomy 21), is the most intensively studied human aneuploidy condition. It is the leading cause of intellectual disability and birth defects. Although most prenatally diagnosed DS fetuses are aborted in Taiwan, there are still some infants with DS who are diagnosed after birth. In addition to intellectual disability, people with DS face systemic problems that include short stature, dysmorphism, congenital heart disease, congenital anomalies of gastrointestinal and genitourinary tracts, abnormal endocrine function, leukemia and leukemoid reactions. To provide better care for people with DS in Taiwan, we began the DS multi-disciplinary clinic that has opened once per month since November 2013. The multi-disciplinary clinic consists of several subspecialists who provide care for DS people. To date, approximately 200 patients have used the clinic. The average number of patients who use the clinic per month is 27±6 with a mean patient age of 16±12 years old (range 0.3-53 years). The average number of patients per specialist on each clinic day is 5.2±4.9 (range 0.5-20.9 patients). We focus on early detection and prevention of medical and developmental issues associated with DS. This coordinated approach allows DS patients and family to have more comprehensive care.

Nationwide survey of extended newborn screening by tandem mass spectrometry in Taiwan.

In Taiwan, during the period March 2000 to June 2009, 1,495,132 neonates were screened for phenylketonuria (PKU) and homocystinuria (HCU), and 1,321,123 neonates were screened for maple syrup urine disease (MSUD), methylmalonic academia (MMA), medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) deficiency, isovaleric academia (IVA), and glutaric aciduria type 1 (GA-1) using tandem mass spectrometry (MS/MS). In a pilot study, 592,717 neonates were screened for citrullinemia, 3-methylcrotonyl-CoA carboxylase deficiency (3-MCC) and other fatty acid oxidation defects in the MS/MS newborn screening. A total of 170 newborns and four mothers were confirmed to have inborn errors of metabolism. The overall incidence was approximately 1/5,882 (1/6,219 without mothers). The most common inborn errors were defects of phenylalanine metabolism [five classic PKU, 20 mild PKU, 40 mild hyperphenylalaninemia (HPA), and 13 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency]. MSUD was the second most common amino acidopathy and, significantly, most MSUD patients (10/13) belonged to the Austronesian aboriginal tribes of southern Taiwan. The most frequently detected among organic acid disorders was 3-MCC deficiency (14 newborns and four mothers). GA-1 and MMA were the second most common organic acid disorders (13 and 13 newborns, respectively). In fatty acid disorders, five carnitine transport defect (CTD), five short-chain acyl-CoA dehydrogenase deficiency (SCAD), and two medium-chain acyl-CoA dehydrogenase (MCAD) deficiency were confirmed. This is the largest case of MS/MS newborn screening in an East-Asian population to date. We hereby report the incidences and outcomes of metabolic inborn error diseases found in our nationwide MS/MS newborn screening program.

Diagnoses of newborns and mothers with carnitine uptake defects through newborn screening.

Carnitine uptake defect (CUD) is an autosomal recessive fatty acid oxidation defect caused by a deficiency of the high-affinity carnitine transporter OCTN2. CUD patients may present with hypoketotic hypoglycemia, hepatic encephalopathy or dilated cardiomyopathy. Tandem mass spectrometry screening of newborns can detect CUD, although transplacental transport of free carnitine from the mother may cause a higher free carnitine level and cause false negatives during newborn screening. From Jan 2001 to July 2009, newborns were screened for low free carnitine levels at the National Taiwan University Hospital screening center. Confirmation tests included dried blood spot free acylcarnitine levels and mutation analyses for both babies and their mothers. Sixteen newborns had confirmation tests for persistent low free carnitine levels; four had CUD, six had mothers with CUD, and six cases were false positives. All babies born to mothers with CUD had transient carnitine deficiency. The six mothers with CUD were put on carnitine supplementation (50-100mg/kg/day). One mother had dilated cardiomyopathy at diagnosis and her cardiac function improved after treatment. Analysis of the SLC22A5 gene revealed that p.S467C was the most common mutation in mothers with CUD, while p.R254X was the most common mutation in newborns and children with CUD. Newborn screening allows for the detection of CUD both in newborns and mothers, with an incidence in newborns of one in 67,000 (95% CI: one in 31,600-512,000) and a prevalence in mothers of one in 33,000 (95% CI: one in 18,700-169,000). Detection of CUD in mothers may prevent them from developing dilated cardiomyopathy.

Mutation of mitochondrial DNA G13513A presenting with Leigh syndrome, Wolff-Parkinson-White syndrome and cardiomyopathy.

Mutation of mitochondrial DNA (mtDNA) G13513A, encoding the ND5 subunit of respiratory chain complex I, can cause mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) and Leigh syndrome. Wolff-Parkinson-White (WPW) syndrome and optic atrophy were reported in a high proportion of patients with this mutation. We report an 18-month-old girl, with an 11-month history of psychomotor regression who was diagnosed with WPW syndrome and hypertrophic cardiomyopathy, in association with Leigh syndrome. Supplementation with coenzyme Q10, thiamine and carnitine prevented further regression in gross motor function but the patient's heart function deteriorated and dilated cardiomyopathy developed 11 months later. She was found to have a mutation of mtDNA G13513A. We suggest that mtDNA G13513A mutation is an important factor in patients with Leigh syndrome associated with WPW syndrome and/or optic atrophy, and serial heart function monitoring by echocardiography is recommended in this group of patients.

Establishing a standardized therapeutic testing protocol for spinal muscular atrophy.

Several mice models have been created for spinal muscular atrophy (SMA); however, there is still no standard preclinical testing system for the disease. We previously generated type III-specific SMA model mice, which might be suitable for use as a preclinical therapeutic testing system for SMA. To establish such a system and test its applicability, we first created a testing protocol and then applied it as a means to investigate the use of valproic acid (VPA) as a possible treatment for SMA. These SMA mice revealed tail/ear/foot deformity, muscle atrophy, poorer motor performances, smaller compound muscle action potential and lower spinal motoneuron density at the age of 9 to 12 months in comparison with age-matched wild-type littermate mice. In addition, VPA attenuates motoneuron death, increases spinal SMN protein level and partially normalizes motor function in SMA mice. These results suggest that the testing protocol developed here is well suited for use as a standardized preclinical therapeutic testing system for SMA.

Poor outcome for neonatal-type nonketotic hyperglycinemia treated with high-dose sodium benzoate and dextromethorphan.

Neonatal-type nonketotic hyperglycinemia treatment remains unsatisfactory, even if started early. A review of six patients who underwent treatment for neonatal-type nonketotic hyperglycinemia in our hospital is presented. All patients were treated with a standardized protocol. Medical histories were retrieved from case notes. All six patients had elevated cerebrospinal fluid plasma glycine levels initially. All but one had received sodium benzoate and dextromethorphan from 1 month of age. All suffered from intractable seizures and severe mental retardation, and only two patients remain alive. One patient died at 5 days of age. No resuscitation was attempted in accordance with the family's wish after genetic counseling. The prognosis of neonatal nonketotic hyperglycinemia remains poor with current treatment. Genetic counseling helps parents cope with this devastating genetic disease.

Maple syrup urine disease presenting with neonatal status epilepticus: report of one case.

Maple syrup urine disease (MSUD) is a rare inborn error of the branched chain amino acid metabolism, which can be classified as classical, intermediate, intermittent, and thiamine responsive types. We report a 16-day-old boy who suffered from difficult feeding, persistent metabolic acidosis, and tricycling movement of the lower legs. Status epilepticus was the initial impression, but classical type MSUD was later diagnosed. Under the diagnosis, dietary therapy effectively prevented further neurological deterioration. However, amino acid deficiency manifested as acrodermatitis enteropathica-like skin rash occurred once. Early parenteral glucose supplementation and periodic plasma amino acid monitoring are very important in the management of metabolic diseases, including MSUD.

Cranial MR spectroscopy of tetrahydrobiopterin deficiency.

BACKGROUND AND PURPOSE: Severe and progressive neurologic disease remains a problem for patients with hyperphenylalaninemia due to a deficiency of tetrahydrobiopterin (BH4), even with early diagnosis and despite treatment with BH4 and neurotransmitter precursors. Few reports have included the associated imaging characteristics. Our purpose was to describe the imaging features of BH4-deficient patients identified by neonatal screening in a Taiwanese population and to correlate the imaging features with the treatment. METHODS: This study analyzed the cases of eight BH4-deficient patients who were examined by MR imaging and MR spectroscopy. Analysis of the findings was correlated with the clinical findings. RESULTS: One patient whose intelligence quotient score was lower than those of the other seven patients experienced seizures in conjunction with central white matter signal changes on MR images and a lactate peak on MR spectroscopy. Lactate peak was revealed in another patient who had marked elevations of N-acetylaspartate:creatine and N-acetylaspartate:choline ratios. Although most patients had a higher than average N-acetylaspartate:creatine or N-acetylaspartate:choline ratio, the patient who had decreases of both ratios possessed the highest intelligence quotient scores among the eight patients. In addition, the myoinositol:choline ratio correlated positively with the average BH4 dosage (P =.027, r = 0.027) and the choline:creatine ratio correlated negatively with the average 5-hydroxytryptophan dosage (P =.035, r = -0.742). CONCLUSION: Compared with classical phenylketonuria, patients with BH4 deficiency have fewer white matter changes revealed by MR imaging but more changes revealed by MR spectroscopy. MR spectroscopy is a potential method with which to monitor the dosages of supplements used to treat this disorder. In addition, MR spectroscopy may be helpful in gaining understanding of the neurophysiological changes that occur in association with this disease.