Geminin restrains mesendodermal fate acquisition of embryonic stem cells and is associated with antagonism of Wnt signaling and enhanced polycomb-mediated repression.

Embryonic cells use both growth factor signaling and cell intrinsic transcriptional and epigenetic regulation to acquire early cell fates. Underlying mechanisms that integrate these cues are poorly understood. Here, we investigated the role of Geminin, a nucleoprotein that interacts with both transcription factors and epigenetic regulatory complexes, during fate acquisition of mouse embryonic stem cells. In order to determine Geminin's role in mesendoderm formation, a process which occurs during embryonic gastrulation, we selectively over-expressed or knocked down Geminin in an in vitro model of differentiating mouse embryonic stem cells. We found that Geminin antagonizes mesendodermal fate acquisition, while these cells instead maintain elevated expression of genes associated with pluripotency of embryonic stem cells. During mesendodermal fate acquisition, Geminin knockdown promotes Wnt signaling, while Bmp, Fgf, and Nodal signaling are not affected. Moreover, we showed that Geminin facilitates the repression of mesendodermal genes that are regulated by the Polycomb repressor complex. Geminin directly binds several of these genes, while Geminin knockdown in mesendodermal cells reduces Polycomb repressor complex occupancy at these loci and increases trimethylation of histone H3 lysine 4, which correlates with active gene expression. Together, these results indicate that Geminin is required to restrain mesendodermal fate acquisition of early embryonic cells and that this is associated with both decreased Wnt signaling and enhanced Polycomb repressor complex retention at mesendodermal genes.

Clinical validity of a brief measure of early childhood social-emotional/behavioral problems.

OBJECTIVE: To address a pressing need for measures of clinically significant social-emotional/behavioral problems in young children by examining several validity indicators for a brief parent-report questionnaire. METHODS: An ethnically and economically diverse sample of 213 referred and nonreferred 2- and 3-year-olds was studied. The validity of the Brief Infant-Toddler Social-Emotional Assessment (BITSEA) Problem Index and Internalizing and Externalizing scales was evaluated relative to a "gold standard" diagnostic interview, as well as the Child Behavior Checklist (CBCL). RESULTS: The validity of the BITSEA Problem Index relative to Diagnosis (sensitivity = 72.7%-80.8%, specificity = 70.0%-83.3%) and clinical-range CBCL scores (sensitivity = 80.0%-96.2%, specificity = 75.0%-89.9%) was supported in the full sample and within minority/nonminority groups. Additional results supported the validity of the BITSEA Internalizing and Externalizing scales. CONCLUSIONS: Documented validity suggests that the BITSEA may be a valuable tool to aid screening, identification, and assessment efforts targeting early-emergent social-emotional/behavioral problems. Practical implications and generalizability are discussed.

The language and culture of delay.

CASE: Satish is a 3 (1/2)-year-old boy you are seeing in your primary care office for a "sick visit" due to parental concerns about his language development. He is the only child of a couple who immigrated to the United States from India shortly before his birth. He received early intervention services for speech and language delays for a few months before he attained 2 years of age. However, services were discontinued when the family moved back to India for a year. After the family returned to the United States, they lived in a different state for several months before moving again recently to his current home, so he is relatively new to your practice. Satish's mother is concerned not only about his communication skills but also about his attention and social skills. She notes that he often plays alone or in parallel with other children. She was also told by his first pediatrician that Satish had "a limited imagination." His parents feel that he has pretend play, in that he will pretend to get his haircut, talk on the phone, or ride on a train. Satish was born at term without complications. He passed his newborn hearing screen and a repeat hearing test at the age of 2 years. He has had no medical problems and takes a daily multivitamin. His parents are both of Indian descent. Satish's father is an engineer and had a history of being a late talker. His mother graduated from high school and is a homemaker. They are expecting their second child. Satish's developmental history is significant for language delays. He babbled at 6 months but did not have single words until he was 2 years. When he was 2 (1/2) years, he had 2 to 3 word sentences. He responded to his name at 15 months and could follow single step commands by the age of 2 years. Currently, Satish is noted to have difficulty with "back and forth conversation." He sometimes repeats what others are saying.The family speaks Hindi, their native language, exclusively at home. When Satish speaks, he usually speaks in Hindi. His parents describe him as using "odd language" in that he will often mix up his pronouns. Satish is in an English-speaking preschool. His preschool teachers report concerns that he seems to "withdraw into his own world," and does not interact well with the other children. They also report attentional problems and poor eye contact.In the office, Satish makes good eye contact with the examiner and his parents. He looks to his parents for approval when completing a task requested of him. He seems to like an Elmo toy that is in the room but holds it and looks at it closely rather than pretend to do anything with it. You ask him to feed Elmo, and he says, "Feed Elmo." Because it is not clear whether he understands the verbal cues given to him, his parents repeat English directions to him in Hindi several times. He eventually complies but then leaves his chair to explore the room. His parents continue to translate your questions to him with variable results. He becomes increasingly difficult to engage, despite repeated attempts, in both English and Hindi, to attract his attention. Where do you go from here?

Clinical genetic testing for patients with autism spectrum disorders.

BACKGROUND: Multiple lines of evidence indicate a strong genetic contribution to autism spectrum disorders (ASDs). Current guidelines for clinical genetic testing recommend a G-banded karyotype to detect chromosomal abnormalities and fragile X DNA testing, but guidelines for chromosomal microarray analysis have not been established. PATIENTS AND METHODS: A cohort of 933 patients received clinical genetic testing for a diagnosis of ASD between January 2006 and December 2008. Clinical genetic testing included G-banded karyotype, fragile X testing, and chromosomal microarray (CMA) to test for submicroscopic genomic deletions and duplications. Diagnostic yield of clinically significant genetic changes was compared. RESULTS: Karyotype yielded abnormal results in 19 of 852 patients (2.23% [95% confidence interval (CI): 1.73%-2.73%]), fragile X testing was abnormal in 4 of 861 (0.46% [95% CI: 0.36%-0.56%]), and CMA identified deletions or duplications in 154 of 848 patients (18.2% [95% CI: 14.76%-21.64%]). CMA results for 59 of 848 patients (7.0% [95% CI: 5.5%-8.5%]) were considered abnormal, which includes variants associated with known genomic disorders or variants of possible significance. CMA results were normal in 10 of 852 patients (1.2%) with abnormal karyotype due to balanced rearrangements or unidentified marker chromosome. CMA with whole-genome coverage and CMA with targeted genomic regions detected clinically relevant copy-number changes in 7.3% (51 of 697) and 5.3% (8 of 151) of patients, respectively, both higher than karyotype. With the exception of recurrent deletion and duplication of chromosome 16p11.2 and 15q13.2q13.3, most copy-number changes were unique or identified in only a small subset of patients. CONCLUSIONS: CMA had the highest detection rate among clinically available genetic tests for patients with ASD. Interpretation of microarray data is complicated by the presence of both novel and recurrent copy-number variants of unknown significance. Despite these limitations, CMA should be considered as part of the initial diagnostic evaluation of patients with ASD.

Language disorders: autism and other pervasive developmental disorders.

This article summarizes current knowledge about language and communication impairments in children who have autism spectrum disorders. It reviews the language profiles that may be observed during the toddler and preschool years and in school-aged children and discusses receptive and expressive language skills that may be quite variable across the spectrum and the universal impairments in pragmatic aspects of language that are among the defining characteristics of the disorder. It concludes with clinical recommendations for pediatric screening of autism spectrum disorders and for continued monitoring of language difficulties in older children for whom interventions may be critical for enhancing effective communication in everyday life.