Refining reproductive risk for FMR1 premutation carriers in the general obstetric population.

Female FMR1 premutation (FMR1 PM) carriers for fragile X syndrome (FXS) are at risk to have a child with FXS based on their CGG repeat size and AGG interruption number. Studies examining this risk in unselected populations of female PM carriers are lacking. This retrospective cohort study analyzed carrier status, CGG repeat length, AGG interruption result, and reproductive risk refinement in a population of female patients who underwent routine carrier screening for FXS. A total of 1536 PM carriers (0.43%) were identified, 95% of whom had between 55 and 90 CGG repeats. A number of 1334 carriers underwent AGG interruption testing. The majority had at least one AGG interruption and received a lower reproductive risk for FXS following AGG interruption testing (89% and 85%, respectively) as compared to their risk calculated based on CGG repeat size alone. The average change in risk across the population following AGG interruption testing was -3.4%, with a range from -50.8% to 48.9%. This article describes the range of CGG repeats and AGG interruptions in an unselected population of female PM carriers and suggests that most carriers would benefit from AGG interruption testing to refine their reproductive risk of having a child with FXS.

Easing the burden of multi-state genetic counseling licensure in the United States: Process, pitfalls, and possible solutions.

State-based genetic counseling licensure creates standardization, ensures high-quality care, and supports the credentialing of genetic counselors (GCs) in the United States. However, it also has the unintended consequence of requiring substantial time and resources from genetic counselors who need to obtain licensure in multiple states. There is a wide range of variability among state licensure applications, required supporting documentation, verification processes, and cost-all of which are barriers for genetic counselors. New licensure laws are being passed on a regular basis, further complicating this process. Resources may be available to some genetic counselors such as employer reimbursement and administrative support; however, access to this support is not universal. This paper reviews the current condition of genetic counseling multi-state licensure, including barriers, unique challenges, and possible solutions for increased efficiencies, based on the authors' experiences and examples found in other healthcare fields.

FMR1 premutation frequency in a large, ethnically diverse population referred for carrier testing.

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and is caused by an expansion of cytosine-guanine-guanine (CGG) repeats in the FMR1 gene. Female premutation allele carriers (55-200 CGG repeats) are at risk to have an affected child. Currently, specific population-based carrier screening for FXS is not recommended. Previous studies exploring female premutation carrier frequency have been limited by size or ethnicity. This retrospective study provides a pan-ethnic estimate of the Fragile X premutation carrier frequency in a large, ethnically diverse population of women referred for routine carrier screening during a specified time period at Progenity, Inc. Patient ethnicity was self-reported and categorized as: African American, Ashkenazi Jewish, Asian, Caucasian, Hispanic, Native American, Other/Mixed/Unknown, or Sephardic Jewish. FXS test results were stratified by ethnicity and repeat allele category. Total premutation carrier frequency was calculated and compared against each ethnic group. A total of 134,933 samples were included. The pan-ethnic premutation carrier frequency was 1 in 201. Only the Asian group differed significantly from this frequency. Using the carrier frequency of 1 in 201, a conservative pan-ethnic risk estimate for a male fetus to have FXS can be calculated as 1 in 2,412. This risk is similar to the highest ethnic-based fetal risks for cystic fibrosis and spinal muscular atrophy, for which population-wide screening is currently recommended. This study adds to the literature and supports further evaluation into specific population-wide screening recommendations for FXS.

Parents' Perspectives on Variants of Uncertain Significance from Chromosome Microarray Analysis.

Chromosomal microarray analysis (CMA) for unexplained anomalies and developmental delay has improved diagnosis rates, but results classified as variants of uncertain significance (VUS) may challenge both clinicians and families. We explored the impact of such results on families, including parental knowledge, understanding and interpretation. Semi-structured telephone interviews were conducted with parents (N = 14) who received genetic counseling for a VUS in their child. Transcripts were analyzed through an iterative coding process. Participants demonstrated a range of recall and personal interpretation regarding whether test results provided a causal explanation for their children's health issues. Participants maintained contradictory interpretations, describing results as answers while maintaining that little clarification of their child's condition had been provided. Reported benefits included obtaining medical services and personal validation. Parents described adaptation/coping processes similar to those occurring after positive test results. Recall of terminology, including "VUS" and precise CMA abnormalities, was poor. However, most demonstrated conceptual understanding of scientific uncertainty. All participants expressed intentions to return for recommended genetics follow-up but had misconceptions about how this would occur. These results provide insight into the patient-and-family experience when receiving uncertain genomic findings, emphasize the importance of exploring uncertainty during the communication process, and highlight areas for potential attention or improvement in the clinical encounter.

A novel intergenic ETnII-ß insertion mutation causes multiple malformations in polypodia mice.

Mouse early transposon insertions are responsible for ~10% of spontaneous mutant phenotypes. We previously reported the phenotypes and genetic mapping of Polypodia, (Ppd), a spontaneous, X-linked dominant mutation with profound effects on body plan morphogenesis. Our new data shows that mutant mice are not born in expected Mendelian ratios secondary to loss after E9.5. In addition, we refined the Ppd genetic interval and discovered a novel ETnII-ß early transposon insertion between the genes for Dusp9 and Pnck. The ETn inserted 1.6 kb downstream and antisense to Dusp9 and does not disrupt polyadenylation or splicing of either gene. Knock-in mice engineered to carry the ETn display Ppd characteristic ectopic caudal limb phenotypes, showing that the ETn insertion is the Ppd molecular lesion. Early transposons are actively expressed in the early blastocyst. To explore the consequences of the ETn on the genomic landscape at an early stage of development, we compared interval gene expression between wild-type and mutant ES cells. Mutant ES cell expression analysis revealed marked upregulation of Dusp9 mRNA and protein expression. Evaluation of the 5' LTR CpG methylation state in adult mice revealed no correlation with the occurrence or severity of Ppd phenotypes at birth. Thus, the broad range of phenotypes observed in this mutant is secondary to a novel intergenic ETn insertion whose effects include dysregulation of nearby interval gene expression at early stages of development.

9p partial monosomy and disorders of sex development: review and postulation of a pathogenetic mechanism.

Deletion of the distal segment of 9p causes a syndrome comprising trigonocephaly, minor anomalies, and intellectual disability. Patients with this condition also frequently present with genitourinary abnormalities including cryptorchidism, hypospadias, ambiguous genitalia, or 46,XY testicular dysgenesis. The region responsible for the gonadal dysgenesis has been localized to 9p24.3 with the likely responsible gene identified as DMRT1. Similar to patients with other molecular causes of 46,XY gonadal dysgenesis, patients with partial del 9p have an increased risk of gonadoblastoma. We present two patients with 46,XY gonadal dysgenesis due to partial 9p monosomy. Both patients were also diagnosed with gonadoblastoma following gonadectomy at an early age. Chromosomal microarray analyses refined the cytogenetic abnormalities and allowed potential genotype-phenotype relationships to be determined. We also review the literature as it pertains to partial 9p monosomy, genital abnormalities and gonadoblastoma and note that a large percentage of affected patients present with two copy number variations. We propose that a two-hit mechanism may be involved in the incomplete penetrance and variable expressivity of partial 9p monosomy and an abnormal genital phenotype. The significant percentage of gonadoblastoma in patients with 46,XY complete gonadal dysgenesis due to partial 9p monosomy also continues to support the necessity of gonadectomy in this patient population.

Analysis of de novo HOXA13 polyalanine expansions supports replication slippage without repair in their generation.

Polyalanine repeat expansion diseases are hypothesized to result from unequal chromosomal recombination, yet mechanistic studies are lacking. We identified two de novo cases of hand-foot-genital syndrome (HFGS) associated with polyalanine expansions in HOXA13 that afforded rare opportunities to investigate the mechanism. The first patient with HFGS was heterozygous for a de novo nine codon polyalanine expansion. Haplotype investigation showed that the expansion arose on the maternally inherited chromosome but not through unequal crossing over between homologs, leaving unequal sister chromatid exchange during mitosis or meiosis or slipped mispairing as possible explanations. The asymptomatic father of the second patient with HFGS was mosaic for a six codon polyalanine expansion. Multiple tissue PCR and clonal analysis of paternal fibroblasts showed only expansion/WT and WT/WT clones, and haplotype data showed that two unaffected offspring inherited the same paternal allele without the expansion, supporting a postzygotic origin. Absence of the contracted allele in the mosaic father does not support sister chromatid exchange in the origin of the expansion. Mosaicism for HOXA13 polyalanine expansions may be associated with a normal phenotype, making examination of parental DNA essential in apparently de novo HFGS cases to predict accurate recurrence risks. We could not find an example in the literature where unequal sister chromatid exchange has been proven for any polyalanine expansion, suggesting that the principal mechanism for polyalanine expansions (and contractions) is slipped mispairing without repair or that the true frequency of unequal sister chromatid exchange involving these repeats is low.

Clinical use of the Surgeon General's "My Family Health Portrait" (MFHP) tool: opinions of future health care providers.

This study examined medical students' and house officers' opinions about the Surgeon General's "My Family Health Portrait" (MFHP) tool. Participants used the tool and were surveyed about tool mechanics, potential clinical uses, and barriers. None of the 97 participants had previously used this tool. The average time to enter a family history was 15 min (range 3 to 45 min). Participants agreed or strongly agreed that the MFHP tool is understandable (98%), easy to use (93%), and suitable for general public use (84%). Sixty-seven percent would encourage their patients to use the tool; 39% would ensure staff assistance. Participants would use the tool to identify patients at increased risk for disease (86%), record family history in the medical chart (84%), recommend preventive health behaviors (80%), and refer to genetics services (72%). Concerns about use of the tool included patient access, information accuracy, technical challenges, and the need for physician education on interpreting family history information.

Exome capture and massively parallel sequencing identifies a novel HPSE2 mutation in a Saudi Arabian child with Ochoa (urofacial) syndrome.

We describe a child of Middle Eastern descent by first-cousin coupling with idiopathic neurogenic bladder and high-grade vesicoureteral reflux at 1 year of age, whose characteristic facial grimace led to the diagnosis of Ochoa (urofacial) syndrome at age 5 years. We used homozygosity mapping, exome capture and paired-end sequencing to identify the disease causing mutation in the proband. We reviewed the literature with respect to the urologic manifestations of Ochoa syndrome. A large region of marker homozygosity was observed at 10q24, consistent with known autosomal recessive inheritance, family consanguinity and previous genetic mapping in other families with Ochoa syndrome. A homozygous mutation was identified in the proband in HPSE2: c.1374_1378delTGTGC, a deletion of 5 nucleotides in exon 10 that is predicted to lead to a frameshift followed by replacement of 132 C-terminal amino acids with 153 novel amino acids (p.Ala458Alafsdel132ins153). This mutation is novel relative to very recently published mutations in HPSE2 in other families. Early intervention and recognition of Ochoa syndrome with control of risk factors and close surveillance will decrease complications and renal failure.