3p14 deletion is a rare contiguous gene syndrome: report of 2 new patients and an overview of 14 patients

Joint contractures is a recurrent clinical feature of individuals with neurodevelopmental disorder due to FOXP1 likely gene disruptive variants

Haploinsufficiency of FOXP1 gene is responsible for a neurodevelopmental disorder presenting with intellectual disability (ID), autism spectrum disorder (ASD), hypotonia, mild dysmorphic features, and multiple congenital anomalies. Joint contractures are not listed as a major feature of FOXP1-related disorder. We report five unrelated individuals, each harboring likely gene disruptive de novo FOXP1 variants or whole gene microdeletion, who showed multiple joint contractures affecting at least two proximal and/or distal joints. Consistent with the phenotype of FOXP1-related disorder, all five patients showed developmental delay with moderate-to-severe speech delay, ID, ASD, and facial dysmorphic features. FOXP1 is implicated in neuronal differentiation and in organizing motor axon projections, thus providing a potential developmental basis for the joint contractures. The combination of joint contractures and neurodevelopmental disorders supports the clinical suspicion of FOXP1-related phenotype.

Contiguous Gene Syndromes and Hearing Loss: A Clinical Report of Xq21 Deletion and Comprehensive Literature Review

Given the crucial role of the personalized management and treatment of hearing loss (HL), etiological investigations are performed early on, and genetic analysis significantly contributes to the determination of most syndromic and nonsyndromic HL cases. Knowing hundreds of syndromic associations with HL, little comprehensive data about HL in genomic disorders due to microdeletion or microduplications of contiguous genes is available. Together with the description of a new patient with a novel 3.7 Mb deletion of the Xq21 critical locus, we propose an unreported literature review about clinical findings in patients and their family members with Xq21 deletion syndrome. We finally propose a comprehensive review of HL in contiguous gene syndromes in order to confirm the role of cytogenomic microarray analysis to investigate the etiology of unexplained HL.

The Genetics of Canine Pulmonary Valve Stenosis

There have been recent advancements in understanding the genetic contribution to pulmonary valve stenosis (PS) in brachycephalic breeds such as the French Bulldog and Bulldog. The associated genes are transcriptions factors involved in cardiac development, which is comparable to the genes that cause PS in humans. However, validation studies and functional follow up is necessary before this information can be used for screening purposes.

Case report: Expanding the phenotype of FOXP1-related intellectual disability syndrome and hyperkinetic movement disorder in differential diagnosis with epileptic seizures

Objective

We aimed to report on previously unappreciated clinical features associated with FOXP1-related intellectual disability (ID) syndrome, a rare neurodevelopmental disorder characterized by global developmental delay, intellectual disability, and language delay, with or without autistic features.

Methods

We performed whole-exome sequencing (WES) to molecularly characterize an individual presenting with ID, epilepsy, autism spectrum disorder, behavioral problems, and facial dysmorphisms as major features.

Results

WES allowed us to identify a previously unreported de novo splice site variant, c.1429-1G>T (NM_032682.6), in the FOXP1 gene (OMIM^*605515) as the causative event underlying the phenotype. Clinical reassessment of the patient and revision of the literature allowed us to refine the phenotype associated with FOXP1 haploinsufficiency, including hyperkinetic movement disorder and flat angiomas as associated features. Interestingly, the patient also has an asymmetric face and choanal atresia and a novel de novo variant of the CHD7 gene.

Conclusion

We suggest that FOXP1-related ID syndrome may also predispose to the development of hyperkinetic movement disorders and flat angiomas. These features could therefore require specific management of this condition.

FOXP1 syndrome: a review of the literature and practice parameters for medical assessment and monitoring

FOXP1 syndrome is a neurodevelopmental disorder caused by mutations or deletions that disrupt the forkhead box protein 1 (FOXP1) gene, which encodes a transcription factor important for the early development of many organ systems, including the brain. Numerous clinical studies have elucidated the role of FOXP1 in neurodevelopment and have characterized a phenotype. FOXP1 syndrome is associated with intellectual disability, language deficits, autism spectrum disorder, hypotonia, and congenital anomalies, including mild dysmorphic features, and brain, cardiac, and urogenital abnormalities. Here, we present a review of human studies summarizing the clinical features of individuals with FOXP1 syndrome and enlist a multidisciplinary group of clinicians (pediatrics, genetics, psychiatry, neurology, cardiology, endocrinology, nephrology, and psychology) to provide recommendations for the assessment of FOXP1 syndrome.

The unique expression profile of FAM19A1 in the mouse brain and its association with hyperactivity, long-term memory and fear acquisition

Neurodevelopment and mature brain function are spatiotemporally regulated by various cytokines and chemokines. The chemokine-like neuropeptide FAM19A1 is a member of family with sequence similarity 19 (FAM19), which is predominantly expressed in the brain. Its highly conserved amino acid sequence among vertebrates suggests that FAM19A1 may play important physiological roles in neurodevelopment and brain function. Here we used a LacZ reporter gene system to map the expression pattern of the FAM19A1 gene in the mouse brain. The FAM19A1 expression was observed in several brain regions starting during embryonic brain development. As the brain matured, the FAM19A1 expression was detected in the pyramidal cells of cortical layers 2/3 and 5 and in several limbic areas, including the hippocampus and the amygdala. FAM19A1-deficient mice were used to evaluate the physiological contribution of FAM19A1 to various brain functions. In behavior analysis, FAM19A1-deficient mice exhibited several abnormal behaviors, including hyperactive locomotor behavior, long-term memory deficits and fear acquisition failure. These findings provide insight into the potential contributions of FAM19A1 to neurodevelopment and mature brain function.

The emerging links between chromosomal instability (CIN), metastasis, inflammation and tumour immunity

Many cancers possess an incorrect number of chromosomes, a state described as aneuploidy. Aneuploidy is often caused by Chromosomal Instability (CIN), a process of continuous chromosome mis-segregation. CIN is believed to endow tumours with enhanced evolutionary capabilities due to increased intratumour heterogeneity, and facilitating adaptive resistance to therapies. Recently, however, additional consequences and associations with CIN have been revealed, prompting the need to understand this universal hallmark of cancer in a multifaceted context. This review is focused on the investigation of possible links between CIN, metastasis and the host immune system in cancer development and treatment. We specifically focus on these links since most cancer deaths are due to the consequences of metastasis, and immunotherapy is a rapidly expanding novel avenue of cancer therapy.

Three Japanese patients with 3p13 microdeletions involving FOXP1

BACKGROUND

FOXP1 is known as the gene responsible for neurodevelopmental delay associated with language impairment. Broad clinical findings also include feeding difficulty, muscular hypotonia, and distinctive features. These findings are common between patients with loss-of-function mutations in FOXP1 and 3p13 microdeletion involving FOXP1. Thus, "FOXP1-related intellectual disability syndrome" is now recommended.

METHODS

After obtaining informed consent, chromosomal microarray testing was performed for patients with unknown etiology.

RESULTS

We identified three Japanese patients with 3p13 microdeletions involving FOXP1. One of the patients showed an additional 1q31.3q32.1 deletion as de novo, which was rather considered as a benign copy number variant.

CONCLUSION

This is the first report of patients with 3p13 microdeletions from Japan. All patients showed growth delay, moderate to severe developmental delay, hearing loss, and distinctive facial features including prominent forehead and mid facial hypoplasia. In addition, "square shaped face" commonly observed in all three patients may be a characteristic finding undescribed previously. From the obtained findings, "FOXP1-related intellectual disability syndrome" was considered to be clinically recognizable.

Interstitial Chromosome 3p13p14 Deletions: An Update and Review

Deletions of proximal chromosome 3p13p14 are infrequent chromosomal alterations. Variable sizes and breakpoints have been reported in patients with a wide range of phenotypes that are evolving as additional cases are reported. The routine use of high-density chromosomal microarrays (CMA) has allowed the identification of many more cases of this disorder and clinical phenotyping shows evidence for an emerging profile among patients with overlapping deletions of 3p13p14. Here, we review the currently reported cases, their phenotypes and where available, the genomic intervals delineated by CMA. Surprisingly, we found that a significant number of proximal chromosome 3p deletions involve structural rearrangements, especially insertions, that have been identified in balanced parental chromosome complements. This region is historically known as a common human chromosomal fragile site, although an underlying genomic mechanism related to its architecture has not been identified. We conclude that identification of an interstitial 3p deletion in a proband by CMA should prompt consideration of further structural chromosomal evaluation using more traditional cytogenetic techniques. While the variability in breakpoints does not suggest a unifying underlying mechanism for these alterations, identification of the haploinsufficient genes in each patient's deletion interval and their developmental roles can guide genotype-phenotype correlations and impact clinical management.

Prospective investigation of FOXP1 syndrome

Background

Haploinsufficiency of the forkhead-box protein P1 (FOXP1) gene leads to a neurodevelopmental disorder termed FOXP1 syndrome. Previous studies in individuals carrying FOXP1 mutations and deletions have described the presence of autism spectrum disorder (ASD) traits, intellectual disability, language impairment, and psychiatric features. The goal of the present study was to comprehensively characterize the genetic and clinical spectrum of FOXP1 syndrome. This is the first study to prospectively examine the genotype-phenotype relationship in multiple individuals with FOXP1 syndrome, using a battery of standardized clinical assessments.

Methods

Genetic and clinical data was obtained and analyzed from nine children and adolescents between the ages of 5–17 with mutations in FOXP1. Phenotypic characterization included gold standard ASD testing and norm-referenced measures of cognition, adaptive behavior, language, motor, and visual-motor integration skills. In addition, psychiatric, medical, neurological, and dysmorphology examinations were completed by a multidisciplinary team of clinicians. A comprehensive review of reported cases was also performed. All missense and in-frame mutations were mapped onto the three-dimensional structure of DNA-bound FOXP1.

Results

We have identified nine de novo mutations, including three frameshift, one nonsense, one mutation in an essential splice site resulting in frameshift and insertion of a premature stop codon, three missense, and one in-frame deletion. Reviewing prior literature, we found seven instances of recurrent mutations and another 34 private mutations. The majority of pathogenic missense and in-frame mutations, including all four missense mutations in our cohort, lie in the DNA-binding domain. Through structural analyses, we show that the mutations perturb amino acids necessary for binding to the DNA or interfere with the domain swapping that mediates FOXP1 dimerization. Individuals with FOXP1 syndrome presented with delays in early motor and language milestones, language impairment (expressive language > receptive language), ASD symptoms, visual-motor integration deficits, and complex psychiatric presentations characterized by anxiety, obsessive-compulsive traits, attention deficits, and externalizing symptoms. Medical features included non-specific structural brain abnormalities and dysmorphic features, endocrine and gastrointestinal problems, sleep disturbances, and sinopulmonary infections.

Conclusions

This study identifies novel FOXP1 mutations associated with FOXP1 syndrome, identifies recurrent mutations, and demonstrates significant clustering of missense mutations in the DNA-binding domain. Clinical findings confirm the role FOXP1 plays in development across multiple domains of functioning. The genetic findings can be incorporated into clinical genetics practice to improve accurate genetic diagnosis of FOXP1 syndrome and the clinical findings can inform monitoring and treatment of individuals with FOXP1 syndrome.

Electronic supplementary material

The online version of this article (10.1186/s13229-017-0172-6) contains supplementary material, which is available to authorized users.

Interstitial Chromosome 3p14.1 Deletion due to a Maternal Insertion: Phenotype and Association with Balanced Parental Rearrangement

Interstitial deletions of 3p14p12 are rare chromosome abnormalities. We present a patient with multiple congenital anomalies and a 15.4-Mb interstitial loss of chromosome 3p14p12 detected by chromosomal microarray (CMA). Our patient shared many phenotypic features with other reported cases involving the same region including prominent forehead, short palpebral fissures, hand and foot anomalies, genital abnormalities, and bilateral hearing loss. Given the clinical similarity of these cases with significant overlap of the deleted regions, it is likely that the phenotype is related to the deletion of specific genes within the region. Further molecular cytogenetic investigation revealed that our patient's rearrangement was derived from a cryptic insertion of a segment of chromosome 3p into chromosome 18q in the mother, which was balanced and therefore not visible on the mother's CMA. To our knowledge, this finding has not been previously reported. This case illustrates the importance of using molecular cytogenetics for structural analysis and parental studies. CMA is commonly the first-line study in patients with multiple congenital anomalies; however, it is not the appropriate modality to define a structural rearrangement that may be the cause of a deletion. The use of adjunct studies to define the mechanism of an identified copy number aberration has direct clinical application: to identify the underlying cause of the chromosomal abnormality and to define the recurrence risk. Additionally, this case adds to the current body of work regarding a recurrent phenotype that can be attributed to interstitial chromosome 3p deletions, which may help define the phenotypic implications of deletions in this region and support early clinical management.

Array-Comparative Genomic Hybridization Analysis in Fetuses with Major Congenital Malformations Reveals that 24% of Cases Have Pathogenic Deletions/Duplications

Karyotyping and aCGH are routinely used to identify genetic determinants of major congenital malformations (MCMs) in fetal deaths or terminations of pregnancy after prenatal diagnosis. Pathogenic rearrangements are found with a variable rate of 9-39% for aCGH. We collected 33 fetuses, 9 with a single MCM and 24 with MCMs involving 2-4 organ systems. aCGH revealed copy number variants in 14 out of 33 cases (42%). Eight were classified as pathogenic which account for a detection rate of 24% (8/33) considering fetuses with 1 or more MCMs and 33% (8/24) taking into account fetuses with multiple malformations only. Three of the pathogenic variants were known microdeletion syndromes (22q11.21 deletion, central chromosome 22q11.21 deletion, and TAR syndrome) and 5 were large rearrangements, adding up to >11 Mb per subject and comprising strong phenotype-related genes. One of those was a de novo complex rearrangement, and the remaining 4 duplications and 2 deletions were 130-900 kb in size, containing 1-7 genes, and were classified as variants of unknown clinical significance. Our study confirms aCGH as a powerful technique to ascertain the genetic etiology of fetal major congenital malformations.