Long-term safety and clinical outcomes of intrathecal heparan-N-sulfatase in patients with Sanfilippo syndrome type A.

INTRODUCTION: Currently, there is no effective therapy for mucopolysaccharidosis IIIA (MPS IIIA). Intravenously-administered enzyme replacement therapies, while effective in other forms of MPS without neurological involvement, have not been successful in patients with MPS IIIA, as they are unable to cross the blood-brain barrier to improve neurological symptoms. We evaluated the long-term safety, tolerability, and clinical outcomes of recombinant human heparan-N-sulfatase (rhHNS) administered intrathecally (IT) in children with MPS IIIA in a phase 1/2 extension study. METHODS: Patients aged ≥3 years with MPS IIIA who had previously completed a phase 1/2 study and received ≥5 of the 6 planned rhHNS infusions via IT administration, were eligible for inclusion. Patients who received 10 mg in the phase 1/2 study had their dose increased to 45 mg. Patients who were treated with 45 mg or 90 mg rhHNS IT in the phase 1/2 study remained on this monthly dose in the extension study. rhHNS was administered via an intrathecal drug delivery device (IDDD). Primary endpoints included the type and severity of adverse events, presence of anti-rhHNS antibodies in the CSF and serum, and changes in laboratory values. Secondary endpoints included standardized neurocognitive assessments and brain magnetic resonance imaging. RESULTS: In the extension study, 12 patients with a mean (SD) age of 9.6 (7.3) years continued treatment with rhHNS IT for a median of 264.4 weeks. Ten of 12 patients completed the extension study. rhHNS IT was generally well-tolerated. All patients experienced at least one treatment-emergent adverse event (TEAE), most being mild or moderate in severity. No serious adverse events (SAEs) were considered related to the study drug, and no deaths occurred. Most SAEs were related to malfunctions of the IDDD. Declines from baseline in Bayley Scales of Infant Development, Third Edition or Kaufman Assessment Battery for Children, Second Edition, Nonverbal Index developmental quotient scores were evident at all rhHNS dosing groups: -17.97%, -18.99%, and -12.12% in the 10/45, 45, and 90 mg groups, respectively, at Month 54. CONCLUSIONS: Overall, rhHNS IT was well tolerated in the extension study. However, rhHNS IT was unable to slow the neurocognitive decline of patients with MPS IIIA. This study was subsequently terminated early because pre-specified efficacy criteria were not met, and the study did not yield clinical proof of concept. (Clinicaltrials.gov Identifier NCT01299727).

Health-Related Quality of Life in Patients With Early-Detected Central Congenital Hypothyroidism.

CONTEXT: Central congenital hypothyroidism (CH) requires lifelong medical treatment. The majority of children with central CH have multiple pituitary hormone deficiencies (MPHD), but in some cases central CH is isolated. Most pituitary hormone deficiencies are associated with impaired health-related quality of life (HRQoL). However, studies on HRQoL in central CH are lacking. OBJECTIVE: To evaluate HRQoL and fatigue in children and young adults with central CH, as well as parent perspectives. DESIGN: Nationwide cross-sectional study comparing HRQoL between early-detected central CH patients and unaffected siblings with the Pediatric Quality of Life inventory (PedsQL™) and PedsQL Multidimensional Fatigue Scale. Participants ≥ 8 years old filled in self-reports; parents of participants aged 3 to 18 years filled in parent reports. Isolated central CH patients, MPHD patients, and siblings were compared using a linear mixed model and Tukey's post hoc test. RESULTS: Eighty-eight patients and 52 siblings participated, yielding 98 self-reports and 115 parent reports. Isolated central CH patients (n = 35) and siblings showed similar scores on all subscales, both in the self-reports and parent reports. For MPHD patients (n = 53), self-reported scores were similar to those of siblings. Parent reported total HRQoL and fatigue scores were significantly poorer in MPHD patients compared with siblings (mean differences -10.2 and -9.4 points; P < 0.01), as were scores for physical functioning, social functioning and general fatigue. CONCLUSION: Self-reported HRQoL scores in isolated central CH and MPHD patients were similar to siblings. However, parents reported significantly lower HRQoL and fatigue scores for MPHD patients, suggesting a difference in perceived limitations between MPHD patients and their parents.

Cognitive and Motor Outcome in Patients with Early-Detected Central Congenital Hypothyroidism Compared with Siblings.

CONTEXT: Early treatment of primary congenital hypothyroidism (CH) prevents irreversible brain damage. Contrary to primary CH, outcome studies on central CH are scarce. Most patients with central CH have multiple pituitary hormone deficiencies (MPHD); these patients are also at risk for neonatal hypoglycemia. OBJECTIVE: To assess cognitive and motor outcome in patients with early-treated central CH detected by the Dutch neonatal screening. METHODS: In this cross-sectional study, primary outcome full-scale intelligence quotient (FSIQ) was measured in patients with MPHD and patients with isolated central CH born between January 1, 1995, and January 1, 2015, with siblings as controls. Secondary outcomes were intelligence test subscales and motor function. Linear mixed models were used to compare both patient groups and siblings, followed by post hoc tests in case of significant differences. RESULTS: Eighty-seven patients (52 MPHD; 35 isolated central CH) and 52 siblings were included. Estimated marginal means for FSIQ were 90.7 (95% CI 86.4-95.0) in patients with MPHD and 98.2 (95% CI 93.0-103.5) in patients with isolated central CH. While patients with MPHD scored lower FSIQs than siblings (mean difference -7.9 points, 95% CI -13.4 to -2.5; P = .002), patients with isolated central CH did not. Processing speed was lower in both patient groups than in siblings (mean differences -10.5 and -10.3 points). Motor difficulties occurred significantly more often in patients (33%) versus siblings (5%; P = .004). CONCLUSION: In early-treated central CH, FSIQ is comparable with siblings in patients with isolated central CH, while patients with MPHD have a significantly lower FSIQ. This may be explained by disease-specific consequences of MPHD, such as neonatal hypoglycemia and more severe hypothyroidism.

The attenuated end of the phenotypic spectrum in MPS III: from late-onset stable cognitive impairment to a non-neuronopathic phenotype.

BACKGROUND: The phenotypic spectrum of many rare disorders is much wider than previously considered. Mucopolysaccharidosis type III (Sanfilippo syndrome, MPS III), is a lysosomal storage disorder traditionally considered to be characterized by childhood onset, progressive neurocognitive deterioration with a rapidly or slowly progressing phenotype. The presented MPS III case series demonstrates adult onset phenotypes with mild cognitive impairment or non-neuronopathic phenotypes. METHODS: In this case series all adult MPS III patients with a mild- or non-neuronopathic phenotype, who attend the outpatient clinic of 3 expert centers for lysosomal storage disorders were included. A mild- or non-neuronopathic phenotype was defined as having completed regular secondary education and attaining a level of independency during adulthood, involving either independent living or a paid job. RESULTS: Twelve patients from six families, with a median age at diagnosis of 43 years (range 3-68) were included (11 MPS IIIA, 1 MPS IIIB). In the four index patients symptoms which led to diagnostic studies (whole exome sequencing and metabolomics) resulting in the diagnosis of MPS III; two patients presented with retinal dystrophy, one with hypertrophic cardiomyopathy and one with neurocognitive decline. The other eight patients were diagnosed by family screening. At a median age of 47 years (range 19-74) 9 out of the 12 patients had normal cognitive functions. Nine patients had retinal dystrophy and 8 patients hypertrophic cardiomyopathy. CONCLUSION: We show the very mild end of the phenotypic spectrum of MPS III, ranging from late-onset stable neurocognitive impairment to a fully non-neuronopathic phenotype. Awareness of this phenotype could lead to timely diagnosis and genetic counseling.

Pediatric Perceived Cognitive Functioning: Psychometric Properties and Normative Data of the Dutch Item Bank and Short Form.

OBJECTIVE: With increasing numbers of children growing up with conditions that are associated with acquired brain injury, efficient neuropsychological screening for cognitive deficits is pivotal. Brief self-report measures concerning daily complaints can play an important role in such screening. We translated and adapted the pediatric perceived cognitive functioning (PedsPCF) self- and parent-report item bank to Dutch. This study presents (1) psychometric properties, (2) a new short form, and (3) normative data for the short form. METHODS: A general population sample of children and parents was recruited. Dimensionality of the PedsPCF was assessed using confirmatory factor analyses and exploratory bifactor analyses. Item response theory (IRT) modeling was used to evaluate model fit of the PedsPCF, to identify differential item functioning (DIF), and to select items for the short form. To select short-form items, we also considered the neuropsychological content of items. RESULTS: In 1441 families, a parent and/or child participated (response rate 66% at family level). Assessed psychometric properties were satisfactory and the predominantly unidimensional factor structure of the PedsPCF allowed for IRT modeling using the graded response model. One item showed meaningful DIF. For the short form, 10 items were selected. CONCLUSIONS: In this first study of the PedsPCF outside the United States, studied psychometric properties of the translated PedsPCF were satisfactory, and allowed for IRT modeling. Based on the IRT analyses and the content of items, we proposed a new 10-item short form. Further research should determine the relation of PedsPCF outcomes with neurocognitive measures and its ability to facilitate neuropsychological screening in clinical practice.

Distress and everyday problems in Dutch mothers and fathers of young adolescents with Down syndrome.

BACKGROUND: To provide targeted support to parents of children with DS, knowledge of their distress and everyday problems is crucial. For this purpose, psychosocial screening instruments can be a valuable addition to routine clinical practice. AIMS: To determine differences on a psychosocial screener concerning distress and everyday problems in parents of young adolescents (YAs) with DS versus control parents and in mothers of YAs with DS versus fathers. METHODS AND PROCEDURES: We compared outcomes of the Distress Thermometer for Parents in 76 mothers and 44 fathers of 11-13-year-olds with DS versus 64 mothers and 52 fathers of age-matched children without DS (comparing mothers and fathers separately). Additionally, we compared mothers and fathers within 34 parent couples of YAs with DS. OUTCOMES AND RESULTS: Clinical distress was not more frequent than in control parents. Mothers further did not report more everyday problems and only differed from their controls on one problem domain and some problem items. Fathers, however, reported more problems than their controls across most domains and wished to talk to a professional about their situation more frequently. Outcomes in mothers and fathers within parent couples did not differ significantly. CONCLUSIONS AND IMPLICATIONS: This is one of few studies to report on the use of psychosocial screening instruments in parents of children with DS. Our results suggested that attention for fathers of YAs with DS is required. Psychosocial screening instruments that inquire about specific problems and the wish for referral can play an important role in achieving this.

Early thyroxine treatment in Down syndrome and thyroid function later in life.

OBJECTIVE: The hypothalamus-pituitary-thyroid (HPT) axis set point develops during the fetal period and first two years of life. We hypothesized that thyroxine treatment during these first two years, in the context of a randomized controlled trial (RCT) in children with Down syndrome, may have influenced the HPT axis set point and may also have influenced the development of Down syndrome-associated autoimmune thyroiditis. METHODS: We included 123 children with Down syndrome 8.7 years after the end of an RCT comparing thyroxine treatment vs placebo and performed thyroid function tests and thyroid ultrasound. We analyzed TSH and FT4 concentrations in the subgroup of 71 children who were currently not on thyroid medication and had no evidence of autoimmune thyroiditis. RESULTS: TSH concentrations did not differ, but FT4 was significantly higher in the thyroxine-treated group than that in the placebo group (14.1 vs 13.0 pmol/L; P = 0.02). There was an increase in anti-TPO positivity, from 1% at age 12 months to 6% at age 24 months and 25% at age 10.7 years with a greater percentage of children with anti-TPO positivity in the placebo group (32%) compared with the thyroxine-treated group (18.5%) (P = 0.12). Thyroid volume at age 10.7 years (mean: 3.4 mL; range: 0.5-7.5 mL) was significantly lower (P < 0.01) compared with reference values (5.5 mL; range: 3-9 mL) and was similar in the thyroxine and placebo group. CONCLUSION: Thyroxine treatment during the first two years of life led to a mild increase in FT4 almost 9 years later on and may point to an interesting new mechanism influencing the maturing HPT axis set point. Furthermore, there was a trend toward less development of thyroid autoimmunity in the thyroxine treatment group, suggesting a protective effect of the early thyroxine treatment. Lastly, thyroid volume was low possibly reflecting Down-specific thyroid hypoplasia.

Growing up with Down syndrome: Development from 6 months to 10.7 years.

BACKGROUND: We analysed developmental outcomes from a clinical trial early in life and its follow-up at 10.7 years in 123 children with Down syndrome. AIMS: To determine 1) strengths and weaknesses in adaptive functioning and motor skills at 10.7 years, and 2) prognostic value of early-life characteristics (early developmental outcomes, parental and child characteristics, and comorbidity) for later intelligence, adaptive functioning and motor skills. METHODS AND PROCEDURES: We used standardized assessments of mental and motor development at ages 6, 12 and 24 months, and of intelligence, adaptive functioning and motor skills at 10.7 years. We compared strengths and weaknesses in adaptive functioning and motor skills by repeated-measures ANOVAs in the total group and in children scoring above-average versus below-average. The prognostic value of demographics, comorbidity and developmental outcomes was analysed by two-step regression. OUTCOMES AND RESULTS: Socialisation was a stronger adaptive skill than Communication followed by Daily Living. Aiming and catching was a stronger motor skill than Manual dexterity, followed by Balance. Above-average and below-average scoring children showed different profiles of strengths and weaknesses. Gender, (the absence or presence of) infantile spasms and particularly 24-month mental functioning predicted later intelligence and adaptive functioning. Motor skills, however, appeared to be less well predicted by early life characteristics. CONCLUSIONS AND IMPLICATIONS: These findings provide a reference for expected developmental levels and strengths and weaknesses in Down syndrome.

Mothers and fathers of young Dutch adolescents with Down syndrome: Health related quality of life and family functioning.

BACKGROUND: Like any child, children with Down syndrome (DS) affect the lives of their families. Most studies focus on the adaptation of parents and families of young children with DS, while relatively few studies include the perspective of fathers. AIMS: To determine 1) whether mothers and fathers of 11 to 13-year-olds with DS differ from reference parents in health related quality of life (HRQoL) and family functioning, and 2) whether HRQoL in parents of children with DS changes over time, from when the child was 6-8 years old to when the child was 11-13 years old. METHODS: 80 mothers and 44 fathers completed HRQoL and family functioning questionnaires. 58 parents (53 mothers) had completed the HRQoL-questionnaire in a previous study. RESULTS: Mothers differed from reference mothers in one HRQoL-domain (Sexuality), while fathers' HRQoL did not significantly differ from reference fathers. Both mothers and fathers scored in the (sub)clinical range more frequently than reference parents in Total family functioning, and in the domains Partner relation and Social network. Furthermore, fathers scored in the (sub)clinical range more frequently than reference parents in Responsiveness and Organization. HRQoL showed no significant change over time. CONCLUSIONS AND IMPLICATIONS: Our findings indicate frequent family functioning problems but few HRQoL problems in parents and families of children with DS. In offering care, a family based approach with special attention for partner relation and social functioning is needed.

A phase 1/2 study of intrathecal heparan-N-sulfatase in patients with mucopolysaccharidosis IIIA.

OBJECTIVE: This was an open-label, phase 1/2 dose-escalation, safety trial of intrathecal recombinant human heparan-N-sulfatase (rhHNS) administered via intrathecal drug delivery device (IDDD) for treating mucopolysaccharidosis IIIA (NCT01155778). STUDY DESIGN: Twelve patients received 10, 45, or 90mg of rhHNS via IDDD once monthly for a total of 6 doses. Primary endpoints included adverse events (AEs) and anti-rhHNS antibodies. Secondary endpoints included standardized neurocognitive assessments, cortical gray matter volume, and pharmacokinetic/pharmacodynamic analyses. RESULTS: All patients experienced treatment-emergent AEs; most of mild-to-moderate severity. Seven patients reported a total of 10 serious AEs (SAEs), all but one due to hospitalization to revise a nonfunctioning IDDD. No SAEs were considered related to rhHNS. Anti-rhHNS antibodies were detected in the serum of 6 patients and in the cerebrospinal fluid (CSF) of 2 of these. CSF heparan sulfate levels were elevated at baseline and there were sustained declines in all tested patients following the first rhHNS dose. No impact of anti-rhHNS antibodies on any pharmacodynamic or safety parameters was evident. 4 of 12 patients showed a decline in developmental quotient, 6 were stable, and 2 patients had only a single data point. No dose group showed a clearly different response pattern. CONCLUSIONS: rhHNS administration via IDDD appeared generally safe and well tolerated. Treatment resulted in consistent declines in CSF heparan sulfate, suggesting in vivo activity in the relevant anatomical compartment. Results of this small study should be interpreted with caution. Future studies are required to assess the potential clinical benefits of rhHNS and to test improved IDDD models.

Early Umbilical Cord Blood-Derived Stem Cell Transplantation Does Not Prevent Neurological Deterioration in Mucopolysaccharidosis Type III.

Mucopolysaccharidosis type III (MPS III), or Sanfilippo disease, is a neurodegenerative lysosomal storage disease (LSD) caused by defective lysosomal degradation of heparan sulfate (HS). No effective disease-modifying therapy is yet available. In contrast to some other neuronopathic LSDs, bone marrow-derived hematopoietic stem cell transplantation (HSCT) fails to prevent neurological deterioration in MPS III patients. We report on the 5-year outcome of early transplantation, i.e., before onset of clinical neurological disease, in combination with the use of umbilical cord blood-derived hematopoietic stem cells (UCBT), in two MPS III patients. Both patients had a normal developmental quotient at the time of UCBT. One patient had a combination of mutations predicting a classical severe phenotype (MPS IIIA), and one patient (MPS IIIB) had mutations predicting a very attenuated phenotype. Transplantation was uncomplicated with full engraftment of donor cells in both.Both patients showed progressive neurological deterioration with regression of cognitive skills and behavioral disturbances during 5 years after successful UCBT, comparable to the natural history of patients with the same combination of mutations. The concentration of HS in CSF in the patient with the attenuated phenotype of MPS IIIB 2 years after UCBT was very high and in the range of untreated MPS III patients.We conclude that the course of cognitive development, behavioral problems, and absence of biochemical correction in CSF demonstrate the absence of relevant effect of UCBT in MPS III patients, even when performed before clinical onset of CNS disease.

Effects of early thyroxine treatment on development and growth at age 10.7 years: follow-up of a randomized placebo-controlled trial in children with Down's syndrome.

CONTEXT: In 2-year-old children with Down's syndrome (DS), early T4 treatment was found to result in slightly better motor development and growth. OBJECTIVES: This study sought to determine long-term effects of early T4 treatment on development and growth in children with DS with either an elevated or normal neonatal TSH concentration. DESIGN: Patients received a single follow-up visit 8.7 years after a randomized placebo-controlled trial (RCT) comparing T4 and placebo treatment during the first 2 years of life. SETTING: Dutch Academic Hospital. PARTICIPANTS: All children who completed the RCT (N = 181, of 196 randomly assigned children) were invited for the follow-up study. A total of 123 participants enrolled, at a mean age of 10.7 years. INTERVENTIONS: T4 or placebo treatment from the neonatal period until 2 years. MAIN OUTCOME MEASURES: Primary: mental and motor development. Secondary: communication skills, fine-motor coordination, height, weight, and head circumference (HC). Outcomes were compared between T4- and placebo-treated children, and between treatment groups with either a normal (<5 mIU/L), or elevated (≥ 5 mIU/L) TSH concentration at original trial entry. RESULTS: Mental or motor development, communication skills, or fine-motor coordination did not differ between T4- (N = 64) and placebo-treated children (N = 59). T4-treated children had a larger HC (50.4 vs 49.8 cm, P = .04) and tended to be taller (133.2 vs 131.1 cm, P = .06). These differences were somewhat greater in children with TSH ≥ 5 mIU/L (HC: T4, 50.5 vs placebo, 49.7 cm; P = .01; height: T4, 133.8 vs placebo, 130.8 cm; P = .02), but were not found in children with TSH <5 mIU/L (HC: T4, 50.1 vs placebo, 50.0 cm; P = .75; height: T4, 132.1 vs placebo, 131.6 cm; P = .22). CONCLUSIONS: Early T4 treatment of children with DS does not seem to benefit mental or motor development later in life. However, the positive effect on growth is still measurable, especially in children with an elevated plasma TSH concentration in the neonatal period.

Health related quality of life in parents of six to eight year old children with Down syndrome.

Raising a child with Down syndrome (DS) has been found to be associated with lowered health related quality of life (HRQoL) in the domains cognitive functioning, social functioning, daily activities and vitality. We aimed to explore which socio-demographics, child functioning and psychosocial variables were related to these HRQoL domains in parents of children with DS. Parents of 98 children with DS completed the TNO-AZL adult quality of life questionnaire (TAAQOL) and a questionnaire assessing socio-demographic, child functioning and psychosocial predictors. Using multiple linear regression analyses for each category of predictors, we selected relevant predictors for the final models. The final multiple linear regression models revealed that cognitive functioning was best predicted by the sleep of the child (ß=.29, p<.01) and by the parent having given up a hobby (ß=-.29, p<.01), social functioning by the quality of the partner relation (ß=.34, p<.001), daily activities by the parent having to care for an ill friend or family member (ß=-.31, p<.01), and vitality by the parent having enough personal time (ß=.32, p<.01). Overall, psychosocial variables rather than socio-demographics or child functioning showed most consistent and powerful relations to the HRQoL domains of cognitive functioning, social functioning, daily activities and vitality. These psychosocial variables mainly related to social support and time pressure. Systematic screening of parents to detect problems timely, and interventions targeting the supportive network and the demands in time are recommended.

Cognitive development in patients with Mucopolysaccharidosis type III (Sanfilippo syndrome).

BACKGROUND: Mucopolysaccharidosis type III (MPS III, Sanfilippo syndrome) is a lysosomal storage disorder caused by a deficiency of one of the enzymes involved in the degradation of heparan sulfate. MPS III is characterized by progressive mental deterioration resulting in severe dementia. A number of potentially disease-modifying therapies are studied. As preservation of cognitive function is the ultimate goal of treatment, assessment of cognitive development will be essential in order to evaluate treatment efficacy. However, no large scale studies on cognitive levels in MPS III patients, using formal psychometric tests, have been reported. METHODS: We aimed to assess cognitive development in all 73 living patients with MPS III in the Netherlands. RESULTS: Cognitive development could be assessed in 69 patients. In 39 of them developmental level was estimated > 3 months and formal psychometric testing was attempted. A remarkable variation in the intellectual disability was detected. CONCLUSIONS: Despite special challenges encountered, testing failed in only three patients. The observed broad variation in intellectual disability, should be taken into account when designing therapeutic trials.