Paternal distress and child behavior problems in low-SES families: Quality of father-child interactions as mediators

This study examines, in low-income families, whether fathers' distress is associated with behavioral problems in preschool children and if the quality of father-child interactions mediates this association. Participants were 81 children between the ages of 3 and 5 years and their parents who were receiving social welfare. Quality of father-child interactions was assessed during a free-play situation and a toy cleanup task, fathers' parenting stress and psychological distress were self-reported, and children's behavior problems were assessed by both parents. Results showed that the quality of father-child interactions during free play, but not during cleanup, partially mediated the link between father distress and child internalizing and externalizing behavior problems. Our findings point to the role of the father-child relationship in the intergenerational transmission of risk in the preschool period. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Autosomal recessive variations of TBX6, from congenital scoliosis to spondylocostal dysostosis

Proximal 16p11.2 microdeletions are recurrent microdeletions with an overall prevalence of 0.03%. In patients with segmentation defects of the vertebra (SDV), a burden of this microdeletion was observed with TBX6 as a candidate gene for SDV. In a published cohort of patients with congenital scoliosis (CS), TBX6 haploinsufficiency was compound heterozygous with a common haplotype. Besides, a single three-generation family with spondylocostal dysostosis (SCD) was reported with a heterozygous stop-loss of TBX6. These observations questioned both on the inheritance mode and on the variable expressivity associated with TBX6-associated SDV. Based on a national recruitment of 56 patients with SDV, we describe four patients with variable SDV ranging from CS to SCD associated with biallelic variations of TBX6. Two patients with CS were carrying a proximal 16p11.2 microdeletion associated with the previously reported haplotype. One patient with extensive SDV was carrying a proximal 16p11.2 microdeletion associated with a TBX6 rare missense change. One patient with a clinical diagnosis of SCD was compound heterozygous for two TBX6 rare missense changes. The three rare variants were affecting the chromatin-binding domain. Our data illustrate the variable expressivity of recessive TBX6 ranging from CS to SCD.

Autosomal recessive IFT57 hypomorphic mutation cause ciliary transport defect in unclassified oral-facial-digital syndrome with short stature and brachymesophalangia

The 13 subtypes of oral-facial-digital syndrome (OFDS) belong to the heterogeneous group of ciliopathies. Disease-causing genes encode for centrosomal proteins, components of the transition zone or proteins implicated in ciliary signaling. A unique consanguineous family presenting with an unclassified OFDS with skeletal dysplasia and brachymesophalangia was explored. Homozygosity mapping and exome sequencing led to the identification of a homozygous mutation in IFT57, which encodes a protein implicated in ciliary transport. The mutation caused splicing anomalies with reduced expression of the wild-type transcript and protein. Both anterograde ciliary transport and sonic hedgehog signaling were significantly decreased in subjects' fibroblasts compared with controls. Sanger sequencing of IFT57 in 13 OFDS subjects and 12 subjects with Ellis-Van Creveld syndrome was negative. This report identifies the implication of IFT57 in human pathology and highlights the first description of a ciliary transport defect in OFDS, extending the genetic heterogeneity of this subgroup of ciliopathies.

Diagnostic odyssey in severe neurodevelopmental disorders: toward clinical whole-exome sequencing as a first-line diagnostic test

The current standard of care for diagnosis of severe intellectual disability (ID) and epileptic encephalopathy (EE) results in a diagnostic yield of ∼50%. Affected individuals nonetheless undergo multiple clinical evaluations and low-yield laboratory tests often referred to as a 'diagnostic odyssey'. This study was aimed at assessing the utility of clinical whole-exome sequencing (WES) in individuals with undiagnosed and severe forms of ID and EE, and the feasibility of its implementation in routine practice by a small regional genetic center. We performed WES in a cohort of 43 unrelated individuals with undiagnosed ID and/or EE. All individuals had undergone multiple clinical evaluations and diagnostic tests over the years, with no definitive diagnosis. Sequencing data analysis and interpretation were carried out at the local molecular genetics laboratory. The diagnostic rate of WES reached 32.5% (14 out of 43 individuals). Genetic diagnosis had a direct impact on clinical management in four families, including a prenatal diagnostic test in one family. Our data emphasize the clinical utility and feasibility of WES in individuals with undiagnosed forms of ID and EE and highlight the necessity of close collaborations between ordering physicians, molecular geneticists, bioinformaticians and researchers for accurate data interpretation.

Homozygous FIBP nonsense variant responsible of syndromic overgrowth, with overgrowth, macrocephaly, retinal coloboma and learning disabilities

The acidic fibroblast growth factor (FGF) intracellular binding protein (FIBP) interacts directly with the fibroblast growth factor FGF1. Although FIBP is known to be implicated in the FGF signaling pathway, its precise function remains unclear. Gain-of-function variants in several FGF receptors (FGFRs) are implicated in a wide spectrum of growth disorders from achondroplasia to overgrowth syndromes. In a unique case from a consanguineous union presenting with overgrowth, macrocephaly, retinal coloboma, large thumbs, severe varicose veins and learning disabilities, exome sequencing identified a homozygous nonsense FIBP variant. The patient's fibroblasts exhibit FIBP cDNA degradation and an increased proliferation capacity compared with controls. The phenotype defines a new multiple congenital abnormalities (MCA) syndrome, overlapping with the heterogeneous group of overgrowth syndromes with macrocephaly. The different clinical features can be explained by the alteration of the FGFR pathway. Taken together, these results suggest the implication of FIBP in a new autosomal recessive MCA.

Clinical reappraisal of SHORT syndrome with PIK3R1 mutations: toward recommendation for molecular testing and management

SHORT syndrome has historically been defined by its acronym: short stature (S), hyperextensibility of joints and/or inguinal hernia (H), ocular depression (O), Rieger abnormality (R) and teething delay (T). More recently several research groups have identified PIK3R1 mutations as responsible for SHORT syndrome. Knowledge of the molecular etiology of SHORT syndrome has permitted a reassessment of the clinical phenotype. The detailed phenotypes of 32 individuals with SHORT syndrome and PIK3R1 mutation, including eight newly ascertained individuals, were studied to fully define the syndrome and the indications for PIK3R1 testing. The major features described in the SHORT acronym were not universally seen and only half (52%) had four or more of the classic features. The commonly observed clinical features of SHORT syndrome seen in the cohort included intrauterine growth restriction (IUGR) <10th percentile, postnatal growth restriction, lipoatrophy and the characteristic facial gestalt. Anterior chamber defects and insulin resistance or diabetes were also observed but were not as prevalent. The less specific, or minor features of SHORT syndrome include teething delay, thin wrinkled skin, speech delay, sensorineural deafness, hyperextensibility of joints and inguinal hernia. Given the high risk of diabetes mellitus, regular monitoring of glucose metabolism is warranted. An echocardiogram, ophthalmological and hearing assessments are also recommended.

Behavior problems of children in foster care: Associations with foster mothers' representations, commitment, and the quality of mother-child interaction

This study investigated different environmental and contextual factors associated with maltreated children's adjustment in foster care. Participants included 83 children (52 boys), ages 1-7 years, and their foster caregivers. Quality of interaction with the foster caregiver was assessed from direct observation of a free-play situation; foster caregiver attachment state of mind and commitment toward the child were assessed using two interviews; disruptive behavior symptoms were reported by foster caregivers. Results showed that quality of interaction between foster caregivers and children were associated with behavior problems, such that higher-quality interactions were related to fewer externalizing and internalizing problems. Foster caregivers' state of mind and commitment were interrelated but not directly associated with behavior problems of foster children. Type of placement moderated the association between foster caregiver commitment and foster child behavior problems. Whereas greater foster caregiver commitment was associated with higher levels of adjustment for children in foster families (kin and non-kin), this was not the case in foster-to-adopt families. Finally, the associations between foster child behavior problems and history of maltreatment and placement related-risk conditions fell below significance after considering child age and quality of interaction with the foster caregiver. Findings underscore the crucial contribution of the foster caregiver-child relationship to fostering child adjustment and, thereby, have important implications for clinical services offered to this population.

A founder haplotype for autosomal dominant sensory ataxia in Eastern Canada

We present phenotypic and genotypic data for an additional family with autosomal dominant sensory ataxia, a disease characterized by gait difficulties associated with diminished sensation in the limbs and areflexia. The same disease haplotype spanning the entire SNAX1 locus is observed in affected members of this second family, enabling the locus to be reduced to a 7.3-cM interval.

A novel autosomal dominant restless legs syndrome locus maps to chromosome 20p13

The authors investigated genetic factors contributing to restless legs syndrome (RLS) by performing a 10-cM genome-wide scan in a large French-Canadian pedigree. They detected an autosomal-dominant locus mapping to chromosome 20p13, with a maximum multipoint lod score of 3.86 at marker D20S849. This is the third reported autosomal-dominant locus for RLS and the first autosomal-dominant RLS locus in the French-Canadian population.

A new locus for autosomal dominant intracranial aneurysm, ANIB4, maps to chromosome 5p15.2-14.3

BACKGROUND

Intracranial aneurysms (IA) are dilatations of intracranial arteries that occur most commonly at arterial bifurcations. Unruptured IA are present in approximately 1-2% of the population aged over 30 years of age. Aneurysms are only rarely symptomatic unless they rupture, which typically results in a subarachnoid haemorrhage associated with high morbidity and mortality.

METHODS

A large French Canadian (FC) family (Aneu60) was identified which contained 12 affected individuals with intracranial aneurysms. Nine of the affected patients and three unaffected individuals were sent for an 8 cM genome-wide scan. Multipoint and two-point methods were used to analyse the scan data by using a dominant parametric model.

RESULTS

We identified an IA susceptibility locus (ANIB4) located on chromosome 5p15.2-14.3. The locus was found by genome-wide linkage analysis and follow up analyses provided a maximum multipoint LOD score of 3.57 over the region. An identical haplotype segment of 7.2 Mb was found in a second FC pedigree and contributes to the refinement of the candidate gene interval.

CONCLUSIONS

Our results indicate that there is a major gene locus on chromosome 5p.

Autism spectrum disorders associated with X chromosome markers in French-Canadian males

It is now well established that genetic factors play an important role in the pathogenesis of autism disorder and converging lines of evidence suggest the implication of the X chromosome. Using a sample of subjects diagnosed with autism spectrum disorders, exclusively composed of males from French-Canadian (FC) origin, we tested markers covering the entire X chromosome using a family-based association study. Our initial analysis revealed the presence of association at two loci: DXS6789 (P=0.026) and DXS8043 (P=0.0101). In a second step, we added support to the association at DXS8043 using additional markers, additional subjects and a haplotype-based analysis (best obtained P-value=0.00001). These results provide support for the existence of a locus on the X chromosome that predisposes the FC to autism spectrum disorders.

The stimulation-induced increase in skeletal muscle glycogen synthase content is impaired in carriers of the glycogen synthase XbaI gene polymorphism

Associations between glycogen synthase gene (GYS1) polymorphism and states of insulin resistance and type 2 diabetes have been reported. The purpose of this study was to establish if the GYS1 genotype impacts on the content of glycogen synthase (GS) protein in muscle measured under basal and stimulated conditions. To examine this, GYS1 XbaI and Met416Val polymorphisms and thigh muscle GYS1 protein content were determined at rest, both before and after several weeks of neuromuscular electrical stimulation in carriers and noncarriers of the mutations. The allelic frequency was 0.086 for the XbaI mutation (A2) and 0.006 for the Met416Val in our cohort of French-Canadian subjects. When measured at rest, the GS protein content in muscle was similar among carriers and noncarriers of the XbaI variant. However, the stimulation-induced increase (23%) in the amount of GS muscle protein normally seen in wildtype individuals was impaired in those carrying the XbaI mutation. These data demonstrate that some individuals, because of their genetic background, are unable to stimulate the process of GS protein accumulation in skeletal muscle. These results could explain why some individuals appear to be genetically predisposed to developing skeletal muscle insulin resistance when exposed to unfavorable metabolic environments.