Down syndrome regression disorder, a case series: Clinical characterization and therapeutic approaches.

Down syndrome (DS) is one of the most frequent genetic disorders and represents the first cause of intellectual disability of genetic origin. While the majority of patients with DS follow a harmonious evolution, an unusual neurodevelopmental regression may occur, distinct from that described in the context of autism spectrum disorders, called down syndrome regression disorder (DSRD). Based on four patients, two males and two females, with age range between 20 and 24, treated at the Reference Center for Rare Psychiatric Disorders of the GHU Paris Psychiatry and Neurosciences [Pôle hospitalo-universitaire d'Évaluation Prévention et Innovation Thérapeutique (PEPIT)], we describe this syndrome, discuss its etiologies and propose therapeutic strategies. DSRD often occurs in late adolescence. There is a sudden onset of language disorders, loss of autonomy and daily living skills, as well as behavioral symptoms such as depression, psychosis, or catatonia. These symptoms are non-specific and lead to an overlap with other diagnostic categories, thus complicating diagnosis. The etiologies of the syndrome are not clearly identified but certain predispositions of patients with trisomy 21 have suggested an underlying immune-mediated mechanism. Symptomatic therapeutic approaches (serotonergic antidepressants, atypical antipsychotics, benzodiazepines) were not effective, and generally associated with poor tolerance. Etiological treatments, including anti-inflammatory drugs and corticosteroids, led to partial or good recovery in the four cases. Early recognition of regressive symptoms and rapid implementation of adapted treatments are required to improve the quality of life of patients and their families.

Three Copies of Four Interferon Receptor Genes Underlie a Mild Type I Interferonopathy in Down Syndrome.

Down syndrome (DS) is characterized by the occurrence of three copies of human chromosome 21 (HSA21). HSA21 contains a cluster of four interferon receptor (IFN-R) genes: IFNAR1, IFNAR2, IFNGR2, and IL10RB. DS patients often develop mucocutaneous infections and autoimmune diseases, mimicking patients with heterozygous gain-of-function (GOF) STAT1 mutations, which enhance cellular responses to three types of interferon (IFN). A gene dosage effect at these four loci may contribute to the infectious and autoimmune manifestations observed in individuals with DS. We report high levels of IFN-αR1, IFN-αR2, and IFN-γR2 expression on the surface of monocytes and EBV-transformed-B (EBV-B) cells from studying 45 DS patients. Total and phosphorylated STAT1 (STAT1 and pSTAT1) levels were constitutively high in unstimulated and IFN-α- and IFN-γ-stimulated monocytes from DS patients but lower than those in patients with GOF STAT1 mutations. Following stimulation with IFN-α or -γ, but not with IL-6 or IL-21, pSTAT1 and IFN-γ activation factor (GAF) DNA-binding activities were significantly higher in the EBV-B cells of DS patients than in controls. These responses resemble the dysregulated responses observed in patients with STAT1 GOF mutations. Concentrations of plasma type I IFNs were high in 12% of the DS patients tested (1.8% in the healthy controls). Levels of type I IFNs, IFN-Rs, and STAT1 were similar in DS patients with and without recurrent skin infections. We performed a genome-wide transcriptomic analysis based on principal component analysis and interferon modules on circulating monocytes. We found that DS monocytes had levels of both IFN-α- and IFN-γ-inducible ISGs intermediate to those of monocytes from healthy controls and from patients with GOF STAT1 mutations. Unlike patients with GOF STAT1 mutations, patients with DS had normal circulating Th17 counts and a high proportion of terminally differentiated CD8+ T cells with low levels of STAT1 expression. We conclude a mild interferonopathy in Down syndrome leads to an incomplete penetrance at both cellular and clinical level, which is not correlate with recurrent skin bacterial or fungal infections. The constitutive upregulation of type I and type II IFN-R, at least in monocytes of DS patients, may contribute to the autoimmune diseases observed in these individuals.

Growth curves for French people with Down syndrome from birth to 20 years of age.

We present new and complete growth charts for 2,598 healthy French children and adolescents with Down syndrome (DS) from 0 to 20 years old, obtained with highly reliable statistical methods. This study is retrospective and addresses data collected over a period of 12 years, monocentric and with a satisfactory representation of the population nationwide. Final occipito-frontal circumference (OFC) is at the fifth percentile compared to WHO charts, with a drop between 12 and 18 months. Final height is at the first percentile compared to WHO charts for girls and boys with two periods of reduced growth velocity: before 36 months and around puberty. We observed no pubertal growth peak for girls. For boys, pubertal growth peak showed to happen earlier and to be less significant than in the general population. When compared to a previous French study with people affected with DS, pubertal growth acceleration begins at a later age for girls and boys; girls in our study are taller at age 15 (+5 cm), but there is no difference for boys at this age. Overweight is more frequent compared to the typical French population. Mean body mass index (BMI) rises rapidly above the 75th percentile of typical French children as early as age 4, with an earlier age for precocious adiposity rebound. The second period for rapid increase of BMI is around 14 years old. When compared to a previous French study with DS, we did not observe any BMI increase, at least up to the age of 14.

Anthropometric charts and congenital anomalies in newborns with Down syndrome.

The objectives of this study were to obtain updated neonatal measurements in French newborns with Down Syndrome (DS) according to their gestational age, and to assess the frequency and distribution of congenital anomalies. Data on congenital malformations, birth weight, birth length and birth occipito-frontal circumference (OFC) according to the gestational age was gathered from 1,030 babies, born between 1980 and 2010. The mean gestational age was 38 weeks from the date of the last menstrual period (LMP) (range: 29-42 weeks). Repartition of complications was found to be similar to previous studies, with no difference according to the date of birth. For girls born after 37 weeks, the mean birth weight was 3,012 ± 430 g, the mean birth length was 47.7 ± 2 cm, and the mean birth OFC was 33 ± 1.4 cm. For boys born after 37 weeks, the mean birth weight was 3,103 ± 459, the mean birth length was 48.4 ± 2.2 cm, and the mean birth OFC was 33.2 ± 1.4 cm. We did not find any difference in these measurements when we compared children born before 1997 and after 2007. When compared to the general population (French data and WHO charts), newborns with DS have a more pronounced difference in their birth length and their birth OFC (15-25th) than in their birth weight (25-50th). The shape of the growth curves shows that growth velocity decreases during the last weeks of gestation in all measurements, which suggests that the modal age for delivery could be earlier in DS newborns than in the general population.

Acute Regression in Young People with Down Syndrome.

Abstract: Adolescents and young adults with Down syndrome (DS) can present a rapid regression with loss of independence and daily skills. Causes of regression are unknown and treatment is most of the time symptomatic. We did a retrospective cohort study of regression cases: patients were born between 1959 and 2000, and were followed from 1984 to now. We found 30 DS patients aged 11 to 30 years old with history of regression. Regression occurred regardless of the cognitive level (severe, moderate, or mild intellectual disability (ID)). Patients presented psychiatric symptoms (catatonia, depression, delusions, stereotypies, etc.), partial or total loss of independence in activities of daily living (dressing, toilet, meals, and continence), language impairment (silence, whispered voice, etc.), and loss of academic skills. All patients experienced severe emotional stress prior to regression, which may be considered the trigger. Partial or total recovery was observed for about 50% of them. In our cohort, girls were more frequently affected than boys (64%). Neurobiological hypotheses are discussed as well as preventative and therapeutic approaches.

Effect of leucovorin (folinic acid) on the developmental quotient of children with Down's syndrome (trisomy 21) and influence of thyroid status.

BACKGROUND: Seven genes involved in folate metabolism are located on chromosome 21. Previous studies have shown that folate deficiency may contribute to mental retardation in Down's syndrome (DS). METHODOLOGY: We investigated the effect of oral folate supplementation (daily dose of 1.0+/-0.3 mg/kg) on cognitive functions in DS children, aged from 3 to 30 months. They received 1 mg/kg leucovorin or placebo daily, for 12 months, in a single-centre, randomised, double-blind study. Folinic acid (leucovorin, LV) was preferred to folic acid as its bioavailability is higher. The developmental age (DA) of the patients was assessed on the Brunet-Lezine scale, from baseline to the end of treatment. RESULTS: The intent-to-treat analysis (113 patients) did not show a positive effect of leucovorin treatment. However, it identified important factors influencing treatment effect, such as age, sex, and concomitant treatments, including thyroid treatment in particular. A per protocol analysis was carried out on patients evaluated by the same examiner at the beginning and end of the treatment period. This analysis of 87 patients (43 LV-treated vs. 44 patients on placebo) revealed a positive effect of leucovorin on developmental age (DA). DA was 53.1% the normal value with leucovorin and only 44.1% with placebo (p<0.05). This positive effect of leucovorin was particularly strong in patients receiving concomitant thyroxin treatment (59.5% vs. 41.8%, p<0.05). No adverse event related to leucovorin was observed. CONCLUSION: These results suggest that leucovorin improves the psychomotor development of children with Down's syndrome, at least in some subgroups of the DS population, particularly those on thyroxin treatment. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00294593.

A 56-year-old female patient with facio-oculo-acoustico-renal syndrome (FOAR) syndrome. Report on the natural history and of a novel mutation.

The facio-oculo-acoustico-renal syndrome (FOAR) is a rare autosomal recessive syndrome characterized by the presence of dysmorphic facial features, ocular anomalies, sensorineural hearing loss, and proteinuria. Diaphragmatic hernia, exomphalos, absent or abnormal corpus callosum, and myopia, can also be part of the syndrome. The disorder is caused by mutations of the LRP2 gene located on chromosome 2q23.3-q31.1. We hereby report the case of a 56-year-old female patient with typical FOAR features. Molecular study of the LRP2 gene revealed the presence of a novel splice-site mutation. In addition to what was reported in FOAR syndrome, this patient had a megadolichocolon complicated by a volvulus and a late-onset renal failure which necessitated hemodyalisis and renal transplantation. Reporting aging patients with genetic syndromes will provide information about their special needs and lead to improvements in their follow-up.