Intelligence and Academic Achievement With Asymptomatic Congenital Cytomegalovirus Infection

OBJECTIVES

To examine intelligence, language, and academic achievement through 18 years of age among children with congenital cytomegalovirus infection identified through hospital-based newborn screening who were asymptomatic at birth compared with uninfected infants.

METHODS

We used growth curve modeling to analyze trends in IQ (full-scale, verbal, and nonverbal intelligence), receptive and expressive vocabulary, and academic achievement in math and reading. Separate models were fit for each outcome, modeling the change in overall scores with increasing age for patients with normal hearing (n = 78) or with sensorineural hearing loss (SNHL) diagnosed by 2 years of age (n = 11) and controls (n = 40).

RESULTS

Patients with SNHL had full-scale intelligence and receptive vocabulary scores that were 7.0 and 13.1 points lower, respectively, compared with controls, but no significant differences were noted in these scores among patients with normal hearing and controls. No significant differences were noted in scores for verbal and nonverbal intelligence, expressive vocabulary, and academic achievement in math and reading among patients with normal hearing or with SNHL and controls.

CONCLUSIONS

Infants with asymptomatic congenital cytomegalovirus infection identified through newborn screening with normal hearing by age 2 years do not appear to have differences in IQ, vocabulary or academic achievement scores during childhood, or adolescence compared with uninfected children.

Neurodevelopmental disabilities in children with intermediate and premutation range fragile X cytosine-guanine-guanine expansions

To determine the range of neurodevelopmental diagnoses associated with intermediate (45-54 repeats) and premutation (55-200 repeats) range cytosine-guanine-guanine fragile X expansions, the medical records of children with intermediate or premutation range expansions were retrospectively reviewed, and all neurodevelopmental diagnoses were abstracted. Twenty-nine children (9 female, 20 male; age, 13 months to 17 years) with intermediate (n = 25) or premutation (n = 4) range expansions were identified with neurodevelopmental diagnoses, including global developmental delay/intellectual disability (n = 15), language and learning disorders (n = 9), attention-deficit hyperactivity disorder (n = 5), epilepsy (n = 5), and motor disorders (n = 12), including 2 boys younger than 4 years of age with tremor and ataxia. Thus, children with intermediate or premutation range fragile X cytosine-guanine-guanine expansions may be more susceptible than children without such expansions to other processes, both genetic and environmental, that contribute to neurodevelopmental disability.

Small rare recurrent deletions and reciprocal duplications in 2q21.1, including brain-specific ARHGEF4 and GPR148

We have identified a rare small (~450 kb unique sequence) recurrent deletion in a previously linked attention-deficit hyperactivity disorder (ADHD) locus at 2q21.1 in five unrelated families with developmental delay (DD)/intellectual disability (ID), ADHD, epilepsy and other neurobehavioral abnormalities from 17 035 samples referred for clinical chromosomal microarray analysis. Additionally, a DECIPHER (http://decipher.sanger.ac.uk) patient 2311 was found to have the same deletion and presented with aggressive behavior. The deletion was not found in either six control groups consisting of 13 999 healthy individuals or in the DGV database. We have also identified reciprocal duplications in five unrelated families with autism, developmental delay (DD), seizures and ADHD. This genomic region is flanked by large, complex low-copy repeats (LCRs) with directly oriented subunits of ~109 kb in size that have 97.7% DNA sequence identity. We sequenced the deletion breakpoints within the directly oriented paralogous subunits of the flanking LCR clusters, demonstrating non-allelic homologous recombination as a mechanism of formation. The rearranged segment harbors five genes: GPR148, FAM123C, ARHGEF4, FAM168B and PLEKHB2. Expression of ARHGEF4 (Rho guanine nucleotide exchange factor 4) is restricted to the brain and may regulate the actin cytoskeletal network, cell morphology and migration, and neuronal function. GPR148 encodes a G-protein-coupled receptor protein expressed in the brain and testes. We suggest that small rare recurrent deletion of 2q21.1 is pathogenic for DD/ID, ADHD, epilepsy and other neurobehavioral abnormalities and, because of its small size, low frequency and more severe phenotype might have been missed in other previous genome-wide screening studies using single-nucleotide polymorphism analyses.