Novel variants underlying autosomal recessive neurodevelopmental disorders with intellectual disability in Iranian consanguineous families

Pathogenic variants in CKAP2L have previously been reported in Filippi Syndrome (FS), a rare autosomal recessive, craniodigital syndrome characterized by microcephaly, syndactyly, short stature, intellectual disability, and dysmorphic facial features. To date, fewer than ten patients with pathogenic variants in CKAP2L associated with FS have been reported. All of the previously reported probands have presumed loss-of-function variants (frameshift, canonical splice site, starting methionine) and all but one have been homozygous for a pathogenic variant. Here we describe two brothers who presented with microcephaly, micrognathia, syndactyly, dysmorphic features, and intellectual disability. Whole exome sequencing of the family identified a missense variant, c.2066G>A (p.Arg689His), in trans with a frameshift variant, c.1169_1173del (p.Ile390LysfsTer4), in CKAP2L. To our knowledge, these are the first patients with FS to be reported with a missense variant in CKAP2L and only the second family to be reported with two variants in trans.

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Comprehensive study of 28 individuals with SIN3A-related disorder underscoring the associated mild cognitive and distinctive facial phenotype

European Journal of Human Genetics ◽

10.1038/s41431-020-00769-7 ◽

2021 ◽

Author(s):

Meena Balasubramanian ◽

Alexander J. M. Dingemans ◽

Shadi Albaba ◽

Ruth Richardson ◽

Thabo M. Yates ◽

...

Keyword(s):

Intellectual Disability ◽

Protein Function ◽

Autism Spectrum ◽

Loss Of Function ◽

Mild Intellectual Disability ◽

Related Disorder ◽

Feeding Difficulties ◽

Facial Phenotype ◽

Novel Variants ◽

Common Behaviour

AbstractWitteveen-Kolk syndrome (OMIM 613406) is a recently defined neurodevelopmental syndrome caused by heterozygous loss-of-function variants in SIN3A. We define the clinical and neurodevelopmental phenotypes related to SIN3A-haploinsufficiency in 28 unreported patients. Patients with SIN3A variants adversely affecting protein function have mild intellectual disability, growth and feeding difficulties. Involvement of a multidisciplinary team including a geneticist, paediatrician and neurologist should be considered in managing these patients. Patients described here were identified through a combination of clinical evaluation and gene matching strategies (GeneMatcher and Decipher). All patients consented to participate in this study. Mean age of this cohort was 8.2 years (17 males, 11 females). Out of 16 patients ≥ 8 years old assessed, eight (50%) had mild intellectual disability (ID), four had moderate ID (22%), and one had severe ID (6%). Four (25%) did not have any cognitive impairment. Other neurological symptoms such as seizures (4/28) and hypotonia (12/28) were common. Behaviour problems were reported in a minority. In patients ≥2 years, three were diagnosed with Autism Spectrum Disorder (ASD) and four with Attention Deficit Hyperactivity Disorder (ADHD). We report 27 novel variants and one previously reported variant. 24 were truncating variants; three were missense variants and one large in-frame gain including exons 10–12.

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Immunity and mental illness: findings from a Danish population-based immunogenetic study of seven psychiatric and neurodevelopmental disorders

European Journal of Human Genetics ◽

10.1038/s41431-019-0402-9 ◽

2019 ◽

Vol 27 (9) ◽

pp. 1445-1455 ◽

Cited By ~ 10

Author(s):

Ron Nudel ◽

Michael E. Benros ◽

Morten Dybdahl Krebs ◽

Rosa Lundbye Allesøe ◽

Camilla Koldbæk Lemvigh ◽

...

Keyword(s):

Intellectual Disability ◽

Protective Effect ◽

Neurodevelopmental Disorders ◽

Association Studies ◽

Human Leukocyte ◽

Population Based ◽

Autism Spectrum ◽

Small Samples ◽

Hla Association ◽

Hla Genes

AbstractHuman leukocyte antigen (HLA) genes encode proteins with important roles in the regulation of the immune system. Many studies have also implicated HLA genes in psychiatric and neurodevelopmental disorders. However, these studies usually focus on one disorder and/or on one HLA candidate gene, often with small samples. Here, we access a large dataset of 65,534 genotyped individuals consisting of controls (N = 19,645) and cases having one or more of autism spectrum disorder (N = 12,331), attention deficit hyperactivity disorder (N = 14,397), schizophrenia (N = 2401), bipolar disorder (N = 1391), depression (N = 18,511), anorexia (N = 2551) or intellectual disability (N = 3175). We imputed participants’ HLA alleles to investigate the involvement of HLA genes in these disorders using regression models. We found a pronounced protective effect of DPB1*1501 on susceptibility to autism (p = 0.0094, OR = 0.72) and intellectual disability (p = 0.00099, OR = 0.41), with an increased protective effect on a comorbid diagnosis of both disorders (p = 0.003, OR = 0.29). We also identified a risk allele for intellectual disability, B*5701 (p = 0.00016, OR = 1.33). Associations with both alleles survived FDR correction and a permutation procedure. We did not find significant evidence for replication of previously-reported associations for autism or schizophrenia. Our results support an implication of HLA genes in autism and intellectual disability, which requires replication by other studies. Our study also highlights the importance of large sample sizes in HLA association studies.

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