Sara M. Sarasua

Prevalence of SHANK3 variants in patients with different subtypes of autism spectrum disorders

Autism spectrum disorders (ASDs) include three main conditions: autistic disorder (AD), pervasive developmental disorder, not otherwise specified (PDD-NOS), and Asperger syndrome. It has been shown that many genes associated with ASDs are involved in the neuroligin–neurexin interaction at the glutamate synapse: NLGN3, NLGN4, NRXN1, CNTNAP2, and SHANK3. We screened this last gene in two cohorts of ASD patients (133 patients from US and 88 from Italy). We found 5/221 (2.3%) cases with pathogenic alterations: a 106 kb deletion encompassing the SHANK3 gene, two frameshift mutations leading to premature stop codons, a missense mutation (p.Pro141Ala), and a splicing mutation (c.1820-4 G>A). Additionally, in 17 patients (7.7%) we detected a c.1304+48C>T transition affecting a methylated cytosine in a CpG island. This variant is reported as SNP rs76224556 and was found in both US and Italian controls, but it results significantly more frequent in our cases than in the control cohorts. The variant is also significantly more common among PDD-NOS cases than in AD cases. We also screened this gene in an independent replication cohort of 104 US patients with ASDs, in which we found a missense mutation (p.Ala1468Ser) in 1 patient (0.9%), and in 8 patients (7.7%) we detected the c.1304+48C>T transition. While SHANK3 variants are present in any ASD subtype, the SNP rs76224556 appears to be significantly associated with PDD-NOS cases. This represents the first evidence of a genotype–phenotype correlation in ASDs and highlights the importance of a detailed clinical-neuropsychiatric evaluation for the effective genetic screening of ASD patients.

22q13.2q13.32 genomic regions associated with severity of speech delay, developmental delay, and physical features in Phelan-McDermid syndrome

Purpose:Phelan–McDermid syndrome is a developmental disability syndrome with varying deletions of 22q13 and varying clinical severity. We tested the hypothesis that, in addition to loss of the telomeric gene SHANK3, specific genomic regions within 22q13 are associated with important clinical features.Methods:We used a customized oligo array comparative genomic hybridization of 22q12.3-terminus to obtain deletion breakpoints in a cohort of 70 patients with terminal 22q13 deletions. We used association and receiver operating characteristic statistical methods in a novel manner and also incorporated protein interaction networks to identify 22q13 genomic locations and genes associated with clinical features.Results:Specific genomic regions and candidate genes within 22q13.2q13.32 were associated with severity of speech/language delay, neonatal hypotonia, delayed age at walking, hair-pulling behaviors, male genital anomalies, dysplastic toenails, large/fleshy hands, macrocephaly, short and tall stature, facial asymmetry, and atypical reflexes. We also found regions suggestive of a negative association with autism spectrum disorders.Conclusion:This work advances the field of research beyond the observation of a correlation between deletion size and phenotype and identifies candidate 22q13 loci, and in some cases specific genes, associated with singular clinical features observed in Phelan–McDermid syndrome. Our statistical approach may be useful in genotype–phenotype analyses for other microdeletion or microduplication syndromes.Genet Med 2014:16(4):318–328.

Autism spectrum disorder in Phelan-McDermid syndrome: initial characterization and genotype-phenotype correlations

BackgroundPhelan-McDermid syndrome (PMS) is a neurodevelopmental disorder associated with a terminal deletion affecting chromosome 22 (22q13) that results in the loss of function of the SHANK3 gene. SHANK3 has also been identified in gene-linkage studies to be associated with autism spectrum disorder (ASD). Diagnosis of ASD in individuals with PMS is complicated by the presence of moderate to profound global developmental delay/intellectual disability as well as other co-morbid systemic and neurological symptoms.MethodsThe current study aimed to characterize the symptoms of ASD in patients with PMS and to do a preliminary exploration of genotype-ASD phenotype correlations. We conducted a standardized interview with 40 parents/guardians of children with PMS. Further, we conducted analyses on the relationship between disruption of SHANK3 and adjacent genes on specific characteristic symptoms of ASD in PMS in small subset of the sample.ResultsThe majority of PMS participants in our sample displayed persistent deficits in Social communication, but only half met diagnostic criteria under the restricted, repetitive patterns of behavior, interests, or activities domain. Furthermore, logistic regressions indicated that general developmental delay significantly contributed to the ASD diagnosis. The analyses relating the PMS genotype to the behavioral phenotype revealed additional complex relationships with contributions of genes in both deleted and preserved SHANK3 regions to the ASD phenotype and other neurobehavioral impairments.ConclusionsThere appears to be a unique behavioral phenotype associated with ASD in individuals with PMS. There also appears to be contributions of genes in both deleted and preserved SHANK3 regions to the ASD phenotype and other neurobehavioral impairments. Better characterization of the behavioral phenotype using additional standardized assessments and further analyses exploring the relationship between the PMS genotype and behavioral phenotype in a larger sample are warranted.

Growth in Phelan-McDermid syndrome.

Phelan–McDermid syndrome (or 22q13.3 deletion syndrome, OMIM #606232) results from a deletion in the terminal region of the long arm of chromosome 22 [Phelan et al., 2001]. Characteristic traits include hypotonia, developmental delay, and severely delayed or absent speech. Minor dysmorphic features are often present, and include long eyelashes, abnormal external ears, large fleshy hands, and hypoor dysplastic toenails [Phelan, 2008]. The growth aspect of the clinical picture of this syndrome is not welldefined. We report growth data on a cohort of 55 patients with terminal 22q13 deletions. Our results help delineate the clinical picture ofPhelan–McDermid syndromeanddemonstrate thenovel observation of occasional undergrowth. The postulation that ‘‘accelerated’’ growth may be a feature of Phelan–McDermid syndrome can be traced to an early report of seven patients with 22q13.3 deletions [Nesslinger et al., 1994]. This assertion was partially based on the observation that while none of the seven patients was undergrown, one had tall stature, one had large hands and feet, and three hadmacrocephaly. Of the three who had macrocephaly, two of their fathers did as well, suggesting the macrocephaly may have been inherited [Weaver and Christian, 1980] independently of the de novo 22q13.3 deletions. One of the two patients with familial macrocephaly was also the patient with tall stature, and head circumference is a known correlate of stature [Bushby et al., 1992], raising furtherquestionof a true associationof overgrowth with the deletion. On the other hand, most previous reports of short stature occurred in patients with ring chromosome 22, so growth failure was dismissed as a phenomenon of any autosomal ring structure rather than deletion of 22q13 [Luciani et al., 2003; Dhar et al., 2010]. Thus, ambiguous and subjective references to advanced or accelerated growth have often been repeated among the list of features of Phelan–McDermid syndrome [Phelan et al., 2001; Jones, 2006; Cusmano-Ozog et al., 2007; Phelan, 2008], although objective evidence has been weak. Wehave collected the largest set of clinical and laboratory data to date on patients with Phelan–McDermid syndrome. Most growth measurements were gathered from physical examinations at Phelan–McDermid Syndrome Foundation conferences in 1998, 2000, 2004, 2006, and 2008; measurements for two additional patients were derived from medical records. This study and the consent forms were approved by the Institutional Review Board of Self Regional Healthcare in Greenwood, South Carolina. After excluding patients with all but terminal deletions of 22q13 (i.e., rings, translocations, interstitial deletions, etc.), the study included growth data on 55 patients (26 males, 29 females) between 10 months and 40 years of age (median age 5.17 years). In five cases where multiple measurements were available from the same patient, only the most recent measurements were used. A total of 45 length/height measurements (19 males, 26 females) and 53 head circumference measurements (25 males, 28 females) were compared by deriving their centiles from the most recent growth references for the United States population [Kuczmarski et al., 2002; Rollins et al., 2010]. One-sample t-tests performed using Stata SE/10 (StataCorp, College Station, TX) revealed that average length-for-age, staturefor-age, andhead circumference-for-age centiles of our patients did not differ significantly from the expected value of 50 (Table I). However, the data appeared to be heavily weighted in the tails; the Chi-square goodness of fit test, also performed using Stata, revealed that the proportion of measurements falling above and below the respective cutoffs for tall and short stature (>95th centile and<5th centile, respectively) was significantly different than expected (P1⁄4 0.0239). The number of patients with short stature equalled

Effect of population stratification on the identification of significant single-nucleotide polymorphisms in genome-wide association studies.

The North American Rheumatoid Arthritis Consortium case-control study collected case participants across the United States and control participants from New York. More than 500,000 single-nucleotide polymorphisms (SNPs) were genotyped in the sample of 2000 cases and controls. Careful adjustment for the confounding effect of population stratification must be conducted when analyzing these data; the variance inflation factor (VIF) without adjustment is 1.44. In the primary analyses of these data, a clustering algorithm in the program PLINK was used to reduce the VIF to 1.14, after which genomic control was used to control residual confounding. Here we use stratification scores to achieve a unified and coherent control for confounding. We used the first 10 principal components, calculated genome-wide using a set of 81,500 loci that had been selected to have low pair-wise linkage disequilibrium, as risk factors in a logistic model to calculate the stratification score. We then divided the data into five strata based on quantiles of the stratification score. The VIF of these stratified data is 1.04, indicating substantial control of stratification. However, after control for stratification, we find that there are no significant loci associated with rheumatoid arthritis outside of the HLA region. In particular, we find no evidence for association of TRAF1-C5 with rheumatoid arthritis.

When folic acid fails: Insights from 20 years of neural tube defect surveillance in South Carolina

Neural tube defects (NTDs) are the most common of the severe malformations of the brain and spinal cord. Increased maternal intake of folic acid (FA) during the periconceptional period is known to reduce NTD risk. Data from 1046 NTD cases in South Carolina were gathered over 20 years of surveillance. It was possible to determine maternal periconceptional FA use in 615 NTD‐affected pregnancies. In 163 occurrent (26.9%) and two recurrent (22%) NTD cases, the mothers reported periconceptional FA use. These women were older and more likely to be white. Maternal periconceptional FA usage was reported in 40.4% of cases of spina bifida with other anomalies but in only 25.2% of isolated spina bifida cases (P = 0.02). This enrichment for associated anomalies was not noted among cases of anencephaly or of encephalocele. Among the 563 subsequent pregnancies to mothers with previous NTD‐affected pregnancies, those taking FA had a 0.4% NTD recurrence rate, but the recurrence without FA was 8.5%. NTDs with other associated findings were less likely to be prevented by FA, suggesting there is a background NTD rate that cannot be further reduced by FA. Nonetheless, the majority (73.9%) of NTDs in pregnancies in which the mothers reported periconceptional FA use were isolated NTDs of usual types. Cases in which FA failed in prevention of NTDs provide potential areas for further study into the causation of NTDs. The measures and techniques implemented in South Carolina can serve as an effective and successful model for prevention of NTD occurrence and recurrence.

Identification of 22q13 genes most likely to contribute to Phelan McDermid syndrome

Chromosome 22q13.3 deletion (Phelan McDermid) syndrome (PMS) is a rare genetic neurodevelopmental disorder resulting from deletions or other genetic variants on distal 22q. Pathological variants of the SHANK3 gene have been identified, but terminal chromosomal deletions including SHANK3 are most common. Terminal deletions disrupt up to 108 protein-coding genes. The impact of these losses is highly variable and includes both significantly impairing neurodevelopmental and somatic manifestations. The current review combines two metrics, prevalence of gene loss and predicted loss pathogenicity, to identify likely contributors to phenotypic expression. These genes are grouped according to function as follows: molecular signaling at glutamate synapses, phenotypes involving neuropsychiatric disorders, involvement in multicellular organization, cerebellar development and functioning, and mitochondrial. The likely most impactful genes are reviewed to provide information for future clinical and translational investigations.

Cholesterol Control Among Uninsured Adults Did Not Improve From 2001‐2004 to 2009‐2012 as Disparities With Both Publicly and Privately Insured Adults Doubled

Background Low‐density lipoprotein cholesterol (LDL‐C) control is higher among insured than uninsured adults, but data on time trends and contributing factors are incomplete and important for improving health equity. Methods and Results Awareness, treatment, and control of elevated LDL‐C were compared among insured versus uninsured and publicly versus privately insured adults, aged 21 to 64 years, in National Health and Nutrition Examination Surveys from 2001 to 2004, 2005 to 2008, and 2009 to 2012 using Adult Treatment Panel‐3 criteria. Compared with insured adults, uninsured adults were younger; were more often minority; reported lower incomes, less education, and fewer healthcare encounters; and had lower awareness and treatment of elevated LDL‐C (P<0.0001). LDL‐C control was higher among insured than uninsured adults in 2001 to 2004 (mean±SEM, 21.4±1.6% versus 10.5±2.6%; P<0.01), and the gap widened by 2009 to 2012 (35.1±1.9% versus 11.3±2.2%; P<0.0001). Despite more minorities (P<0.01), greater poverty, and less education (P<0.001), publicly insured adults had more healthcare visits/year than privately insured adults (P<0.001) and similar awareness, treatment, and control of LDL‐C from 2001 to 2012. In multivariable logistic regression, significant positive predictors of cholesterol awareness, treatment, and control included more frequent health care (strongest), increasing age, private healthcare insurance versus uninsured, and hypertension. Public insurance (versus uninsured) was a significant positive predictor of LDL‐C control, whereas income <200% versus ≥200% of federal poverty was a significant negative predictor. Conclusions LDL‐C control improved similarly over time in publicly and privately insured adults but was stagnant among the uninsured. Healthcare insurance largely addresses socioeconomic barriers to effective LDL‐C management, yet poverty retains an independent adverse effect.

Letter to the editor regarding Disciglio et al.: Interstitial 22q13 deletions not involving SHANK3 gene: A new contiguous gene syndrome

Letter to the Editor Regarding Disciglio et al.: Interstitial 22q13 Deletions not Involving SHANK3 Gene: A New Contiguous Gene Syndrome Katy Phelan,* Luigi Boccuto, R. Curtis Rogers, Sara M. Sarasua, and Heather E. McDermid Department of Pediatrics, Hayward Genetics Center, Tulane University School of Medicine, New Orleans, Louisiana Greenwood Genetic Center, Greenwood, South Carolina Biological Sciences, University of Alberta, Edmonton, Alberta, Canada

Opportunities for improving cardiovascular health outcomes in adults younger than 65 years with guideline-recommended statin therapy

The impact of age, race/ethnicity, healthcare insurance, and selected clinical variables on statin‐preventable ASCVD were quantified in adults aged 21 to 79 years from National Health and Nutrition Examination Surveys 2007–2012 using the 2013 American College of Cardiology/American Heart Association guideline on the treatment of cholesterol. Among ≈42.4 million statin‐eligible, untreated adults, 52.6% were hypertensive and 71% were younger than 65 years. Of ≈232 000 statin‐preventable ASCVD events annually, most occur in individuals younger than 65 years, with higher proportions in blacks and Hispanics than whites (73.0% and 69.2% vs 56.9%, respectively; P<.01). Among adults younger than 65 years, the ratio of statin‐eligible but untreated to statin‐treated adults was higher in blacks and Hispanics than whites (3.0 and 2.9 vs 1.3, respectively; P<.01), and blacks, men, hypertensives, and cigarette smokers were more likely to be statin eligible than their statin‐ineligible counterparts by multivariable logistic regression. Two thirds of untreated statin‐eligible adults had two or more healthcare visits per year. Identifying and treating more statin‐eligible adults in the healthcare system could improve cardiovascular health equity.