Whole‐exome sequencing has established IQSEC2 as a neurodevelopmental disability gene. The IQSEC2 variant phenotype includes developmental delay, intellectual disability, epilepsy, hypotonia, autism, developmental regression, microcephaly and stereotypies but is yet to be fully described. Presented here are 14 new patients with IQSEC2 variants. In addition to the established features, we observed: gait ataxia in 7 of 9 (77.8%), drooling in 9 of 14 (64.2%), early feeding difficulties in 7 of 14 (50%), structural brain abnormalities in 6 of 13 (46.2%), brachycephaly in 5 of 14 (35.7%), and scoliosis and paroxysms of laughter each in 4 of 14 (28.6%). We suggest that these are features of the IQSEC2‐related disorder. Gastrostomy requirement, plagiocephaly, strabismus and cortical blindness, each seen in 2 of 14 (14.3%), may also be associated. Shared facial features were noted in 8 of 14 patients, and shared hair patterning was identified in 5 of 14 patients. This study further delineates the IQSEC2 phenotypic spectrum and supports the notion of an emerging IQSEC2 syndrome. We draw parallels between the IQSEC2‐related disorder and the Angelman‐/Rett‐/Pitt‐Hopkins syndrome group of conditions and recommend the addition of IQSEC2 to epilepsy and developmental delay gene panels. We observed discordant phenotypes in monozygotic twins and apparent gonadal mosaicism, which has implications for recurrence risk counselling in the IQSEC2‐related disorder.

This report includes a review of IJO and genetic causes of osteoporosis, and suggests that existing cases of IJO should be screened for PLS3. Through analysis of bone material properties in Patient 2, we can conclude that PLS3 does have a role in bone mineralisation.

Introduction Preterm birth (<37 weeks) adversely affects development in behavioural, cognitive and mental health domains. Heightened rates of autism are identified in preterm populations, indicating that prematurity may confer an increased likelihood of adverse neurodevelopmental outcomes. The present meta-analysis aims to synthesise existing literature and calculate pooled prevalence estimates for rates of autism characteristics in preterm populations. Methods Search terms were generated from inspection of relevant high-impact papers and a recent meta-analysis. Five databases were searched from database creation until December 2020 with PRISMA guidelines followed throughout. Results 10,900 papers were retrieved, with 52 papers included in the final analyses, further classified by assessment method (screening tools N=30, diagnostic assessment N=29). Pooled prevalence estimates for autism in preterm samples was 20% when using screening tools and 6% when using diagnostic assessments. The odds of an autism diagnosis were 3.3 times higher in individuals born preterm than in the general population. Conclusions The pooled prevalence estimate of autism characteristics in individuals born preterm is considerably higher than in the general population. Findings highlight the clinical need to provide further monitoring and support for individuals born preterm.

In the original publication of this article [1] the following data points were missing from Table 1 (pages 6 & 7) due to a word processing error. a. Mir et al., 2020 -Quality weightings of ' Autism -2' 'Sample Identification -1' 'Design -2' . b. Vermeirsch et al., 2020 -Quality weightings of ' Autism -2' 'Sample Identification -1' 'Design.The correct Table 1 is shown in the next pages. Two author's affiliations have been amended to be

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