Chromosome microarrays in diagnostic testing: interpreting the genomic data

Genome-Wide Array Analysis Reveals Novel Genomic Regions and Candidate Gene for Intellectual Disability

INTRODUCTION

Intellectual disability (ID) is often sporadic, and its complex etiology makes clinical diagnosis extremely difficult.

OBJECTIVE

The aims of this study were to detect copy number variations (CNVs) in patients with ID and to analyze the correlation between pathogenic CNVs and clinical phenotype.

METHODS

After cases of ID caused by metabolic dysfunction or environmental factors were excluded, 64 patients with moderate to severe ID were enrolled. Karyotype and single nucleotide polymorphism (SNP) array analyses were performed for all patients. The relationship between CNVs and phenotype was identified with genotype-phenotype comparisons and by searching CNV databases.

RESULTS

Karyotype analysis showed four patients with chromosomal aneuploidy and seven with chromosomal structural abnormality. After excluding the four cases with chromosomal aneuploidy, the remaining 60 cases were analyzed using SNP array. The results revealed 87 CNVs in 45 cases, including 16 pathogenic CNVs in 12 individuals, with a diagnostic yield of 20.0% (12/60). We found large deletions at 16q22.2q23.1 and 3q24q25.32 in two patients, respectively, in whom specific syndromes had not been defined. Our array analysis showed one case carried a 210 kb deletion at 1p21.2p21.3, which included only one coding gene LPPR4, which might be a candidate gene for ID phenotype.

CONCLUSIONS

Use of the genome-wide array method can improve the detection rate of CNVs, reveal chromosomal abnormalities that have not been well-characterized by cytology, and provide a new way to locate genes for patients with the ID phenotype. Interpretation of CNVs remains a major challenge. Sharing of CNVs and phenotype information from different laboratories in public databases is important.

Translating Research to Practice for Children With Autism Spectrum Disorder: Part I: Definition, Associated Behaviors, Prevalence, Diagnostic Process, and Interventions

INTRODUCTION

The number of children with autism spectrum disorder (ASD) is rising, along with the potential for challenging behaviors during health care encounters.

METHOD

We present an overview of the emerging science related to ASD diagnosis and interventions for children with ASD.

RESULTS

Emerging science on ASD reveals common associated challenging behaviors, increasing prevalence, emphasis on early diagnosis at 18 to 24 months of age, changes in the diagnostic process with criteria from the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, and interventions with medication, education, and behavior management.

DISCUSSION

Family and health care provider preparation strategies facilitate care of children with ASD and their families. Early diagnosis at 18 to 24 months of age and evidence-based interventions contribute to best outcomes for children and families. Health care providers must be aware of the state of the science for diagnosis and best practices to provide family-centered care for this growing population.