Characterization of PARP6 Function in Knockout Mice and Patients with Developmental Delay.

PARP6, a member of a family of enzymes (17 in humans) known as poly-ADP-ribose polymerases (PARPs), is a neuronally enriched PARP. While previous studies from our group show that Parp6 is a regulator of dendrite morphogenesis in rat hippocampal neurons, its function in the nervous system in vivo is poorly understood. Here, we describe the generation of a Parp6 loss-of-function mouse model for examining the function of Parp6 during neurodevelopment in vivo. Using CRISPR-Cas9 mutagenesis, we generated a mouse line that expressed a Parp6 truncated variant (Parp6TR) in place of Parp6WT. Unlike Parp6WT, Parp6TR is devoid of catalytic activity. Homozygous Parp6TR do not exhibit obvious neuromorphological defects during development, but nevertheless die perinatally. This suggests that Parp6 catalytic activity is important for postnatal survival. We also report PARP6 mutations in six patients with several neurodevelopmental disorders, including microencephaly, intellectual disabilities, and epilepsy. The most severe mutation in PARP6 (C563R) results in the loss of catalytic activity. Expression of Parp6C563R in hippocampal neurons decreases dendrite morphogenesis. To gain further insight into PARP6 function in neurons we also performed a BioID proximity labeling experiment in hippocampal neurons and identified several microtubule-binding proteins (e.g., MAP-2) using proteomics. Taken together, our results suggest that PARP6 is an essential microtubule-regulatory gene in mice, and that the loss of PARP6 catalytic activity has detrimental effects on neuronal function in humans.

Novel 47.5-kb deletion in RAB27A results in severe Griscelli Syndrome Type 2.

Griscelli syndrome (GS), a rare autosomal recessive disorder characterized by partial albinism and immunological impairment and/or severe neurological impairment, results from mutations in the MYO5A (GS1), RAB27A (GS2), or MLPH (GS3) genes. We identified a Hispanic patient born of a consanguineous union who presented with immunodeficiency, partial albinism, hepatic dysfunction, hemophagocytosis, neurological impairment, nystagmus, and silvery hair indicative of Griscelli Syndrome Type 2 (GS2). We screened for point mutations, but only exons 2-6 of the patient's DNA could be PCR-amplified. Whole genome analysis using the Illumina 1M-Duo DNA Analysis BeadChip identified a homozygous deletion in the patient's DNA. The exact breakpoints of the 47.5-kb deletion were identified as chr15q15-q21.1: g.53332432_53379990del (NCBI Build 37.1); the patient lacks the promoter and 5'UTR regions of RAB27A, thus confirming the diagnosis of GS2.

Correlation between rare chromosomal abnormalities and prenatal ultrasound findings.

Our objective was to examine ultrasound findings with outcomes in cases of rare chromosomal abnormalities diagnosed during pregnancy. Results of cytogenetic studies obtained from amniocenteses and chorionic villus samplings (CVS) from 1994-2000 were reviewed. Only those examples of rare chromosomal abnormalities with little information on the associated outcome were included. Cases of autosomal trisomy (13, 18, and 21), sex chromosome aneuploidy, and reciprocal or Robertsonian translocations were excluded. Ultrasound findings and outcomes were reviewed. In all, 8,642 procedures of amniocenteses and 557 of CVS were performed; 21 cases met the inclusion criteria. Parental karyotypes were obtained for 19 couples and the karyotypic abnormalities were de novo in 13. Abnormal ultrasound findings were present in 14 pregnancies, with the following outcomes: seven underwent dilatation and evacuation (D&E), with abnormal findings in two (although examination was limited by fragmentation); one medical termination with micrognathia and low-set ears; one fetal demise; one neonatal demise; three surviving neonates with abnormalities (one each with congenital kyphosis, hydronephrosis, and hypotonia), and one newborn was normal. There were seven patients without abnormal ultrasound findings with the following outcomes: three underwent D&E, with abnormal findings in two, one child with a colobomatous optic nerve, and two apparently normal infants. Follow-up was not available in one patient. We conclude that when rare karyotypes and ultrasound abnormalities are present, poor outcomes are likely. Even with normal ultrasound findings, abnormalities may be present. These data may assist in counseling patients when testing reveals such chromosomal abnormalities.

Allelic imbalance in selected chromosomal regions in ovarian cancer.

Ovarian cancer (OC) is often asymptomatic at the initial stage. When diagnosed, up to 75% of the patients present grade III or IV tumors with metastasis in nearby organs of the abdomen. Genetic imbalance is abundant in OC, and allelic loss (AL) of specific chromosomal regions is considered an early event. To establish association between genetic markers for early diagnosis/prognosis of OC, our target was to define narrow specific regions of AL. We analyzed 65 ovarian carcinomas by using 19 microsatellite markers located in three different chromosomes. First, a 7.6-Mb region containing the estrogen receptor (ESR1) and the tumor suppressor gene LATS1 was analyzed. Several chromosomal breakpoints flanking ESR1 affecting the region harboring LATS1 were found. Second, we found chromosomal breakpoints on 13q13.1 approximately q13.3 that defined two narrow regions flanking the BRCA2 locus. Third, our ovarian tumors exhibited a very high frequency of AL on 16q and chromosomal breakpoints defining two narrow regions within 16q22.2 approximately q24.3. In this article, we report three new polymorphic microsatellite markers and strong evidence of AL of narrow well-defined regions in hot spots on 6q, 13q, and 16q in ovarian tumors.

Frequent LOH at hMLH1, a highly variable SNP in hMSH3, and negligible coding instability in ovarian cancer.

BACKGROUND: Molecular alterations such as DNA microsatellite instability (MSI/RER), single nucleotide polymorphism (SNP) and loss of heterozygosity (LOH) can occur throughout the genome and be associated with different types of cancer. In the present study, we aimed at detecting molecular alterations within the mismatch DNA repair genes in ovarian cancer (OC), using a sensitive, accurate and reliable protocol we have developed. MATERIALS AND METHODS: A combination of high-resolution GeneScan software analysis and automated DNA cycle sequencing was used. RESULTS: Negligible coding MSI was observed in selected sequences of mismatch DNA repair genes in our series of sixty-two ovarian tumors and matched blood DNAs. Unlike MSI, loss of one hMLH1 allele was scored in almost half (47%) of the informative cases. In addition, an SNP in hMSH3/intron 5 was found to be highly variable in OC patients. CONCLUSION: 1) Coding DNA instability is likely to be a very rare event in OC and, therefore, may not significantly contribute to the development of OC, and 2) the high frequency of LOH at hMLH1 observed in our ovarian tumors suggests that further investigation is needed to determine if such a trend exists in other mismatch DNA repair and/or critical genes.

Substance Abuse in Hawaii: Perspectives of Key Local Human Service Organizations.

Available evidence suggests that substance abuse in Hawaii is a substantial problem. The three major objectives of this study were to determine qualitatively Hawaii's human service organizations' perspective regarding (1) the magnitude of the statewide substance abuse problem, (2) the unmet needs of the state's substance abuse treatment system, and (3) the features of the problem unique to Hawaii's many ethnic and other subgroups. The study targeted those human service organizations most burdened by the substance abuse problem. Respondents from 55 human service organizations were interviewed using a series of 21 open-ended questions. Respondents perceived the magnitude of the Hawaii substance abuse problem to be at least comparable to that of the mainland United States. Although most respondents viewed the problem using a medical model, the problem was generally thought to be exacerbated by a community context in which substance abuse is accepted, excused, or denied. Increasing use of crystal methamphetamine and heroin were cited as the most worrisome trends. Systems issues identified were unstable funding, insufficient detoxification services, and limited availability of residential treatment and supportive services following treatment, such as housing and aftercare. Service delivery problems frequently associated with rural areas were identified, such as transportation, staff development, outreach, and difficulty providing a full range of services, particularly on neighbor islands. Cultural alienation, exacerbated by the state's prevailing multiculturalism, was thought to contribute to the substance abuse problem among all ethnic groups, but especially among Native Hawaiians. Cultural factors were thought to have a major impact on seeking care and subsequent acceptance of such care. Further study is needed to understand better the content of care, therapeutic elements, and efficacy of culturally specific treatment and prevention programs. To initiate change, concerted efforts are needed to inform Hawaii residents about the statewide substance abuse problem and local treatment system needs. Future studies should compare human service organization perceptions to those of individuals abusing substances and using these services.

Characterization of a complex rearrangement involving duplication and deletion of 9p in an infant with craniofacial dysmorphism and cardiac anomalies.

Partial duplication and partial deletion of the short arm of chromosome 9 have each been reported in the literature as clinically recognizable syndromes. We present clinical, cytogenetic, and molecular findings on a five-week-old female infant with concomitant duplication and terminal deletion of the short arm of chromosome 9. To our knowledge ten such cases have previously been reported. Conventional cytogenetic analysis identified additional material on chromosome 9 at band p23. FISH analysis aided in determining the additional material consisted of an inverted duplication with a terminal deletion of the short arm. Microarray analysis confirmed this interpretation and further characterized the abnormality as a duplication of about 32.7 Mb, from 9p23 to 9p11.2, and a terminal deletion of about 11.5 Mb, from 9p24.3 to 9p23. The infant displayed characteristic features of Duplication 9p Syndrome (hypotonia, bulbous nose, single transverse palmar crease, cranial anomalies), as well as features associated with Deletion 9p Syndrome (flat nasal bridge, long philtrum, cardiac anomalies) despite the deletion being distal to the reported critical region for this syndrome. This case suggests that there are genes or regulatory elements that lie outside of the reported critical region responsible for certain phenotypic features associated with Deletion 9p Syndrome. It also underscores the importance of utilizing array technology to precisely define abnormalities involving the short arm of 9p in order to further refine genotype/phenotype associations and to identify additional cases of duplication/deletion.

Array-based FMR1 sequencing and deletion analysis in patients with a fragile X syndrome-like phenotype.

BACKGROUND: Fragile X syndrome (FXS) is caused by loss of function mutations in the FMR1 gene. Trinucleotide CGG-repeat expansions, resulting in FMR1 gene silencing, are the most common mutations observed at this locus. Even though the repeat expansion mutation is a functional null mutation, few conventional mutations have been identified at this locus, largely due to the clinical laboratory focus on the repeat tract. METHODOLOGY/PRINCIPAL FINDINGS: To more thoroughly evaluate the frequency of conventional mutations in FXS-like patients, we used an array-based method to sequence FMR1 in 51 unrelated males exhibiting several features characteristic of FXS but with normal CGG-repeat tracts of FMR1. One patient was identified with a deletion in FMR1, but none of the patients were found to have other conventional mutations. CONCLUSIONS/SIGNIFICANCE: These data suggest that missense mutations in FMR1 are not a common cause of the FXS phenotype in patients who have normal-length CGG-repeat tracts. However, screening for small deletions of FMR1 may be of clinically utility.

Infertility and abnormal cervical mucus in two sisters who are compound heterozygotes for the cystic fibrosis (CF) DeltaF508 and R117H/7T mutations.

OBJECTIVE: To describe two cases of infertile sisters who are compound heterozygote carriers of the cystic fibrosis (CF) DeltaF508 and R117H/7T mutations and who were found to have significantly abnormal cervical mucus. DESIGN: Case reports and review of literature. SETTING: Infertility practice based in an academic medical center. PATIENT(S): Two sisters (ages 34 and 42), compound heterozygote carriers of CF mutations, who presented with involuntary infertility. INTERVENTION(S): The partners of both patients tested negative for CF. The evaluation of both sisters did not indicate other causes of infertility aside from advanced maternal age in the 42-year-old patient. Both sisters underwent natural-cycle intrauterine insemination. MAIN OUTCOME MEASURE(S): Pregnancy conception. RESULT(S): The 34-year-old patient has subsequently conceived twice through natural-cycle inseminations. CONCLUSION(S): This is the first reported case of infertility due to a cervical mucus factor in a patient who is a compound heterozygote of the DeltaF508 and R117H/7T mutations. This case is important not only because of the distinct phenotypic abnormality seen with specific CF mutations but also because of the associated genotype.

TBX5 genetic testing validates strict clinical criteria for Holt-Oram syndrome.

Holt-Oram syndrome (HOS) is an autosomal dominant heart-hand syndrome characterized by congenital heart disease (CHD) and upper limb deformity, and caused by mutations in the TBX5 gene. To date, the sensitivity of TBX5 genetic testing for HOS has been unclear. We now report mutational analyses of a nongenetically selected population of 54 unrelated individuals who were consecutively referred to our center with a clinical diagnosis of HOS. TBX5 mutational analyses were performed in all individuals, and clinical histories and findings were reviewed for each patient without reference to the genotypes. Twenty-six percent of the complete cohort was shown to have mutations of the TBX5 gene. However, among those subjects for whom clinical review demonstrated that their presentations met strict diagnostic criteria for HOS, TBX5 mutations were identified in 74%. No mutations were identified in those subjects who did not meet these criteria. Thus, these studies validate our clinical diagnostic criteria for HOS including an absolute requirement for preaxial radial ray upper limb malformation. Accordingly, TBX5 genotyping has high sensitivity and specificity for HOS if stringent diagnostic criteria are used in assigning the clinical diagnosis.

Preimplantation genetic diagnosis of human congenital heart malformation and Holt-Oram syndrome.

Holt-Oram syndrome (HOS) is a multiple malformation syndrome associated with congenital heart malformation (CHM) and caused by mutations in the TBX5 transcription factor. Effective prenatal genetic diagnosis of HOS is limited by factors that modify clinical manifestations and confound prediction of an individual's phenotype. Although preimplantation genetic diagnosis (PGD) has been applied to complex disorders with some cardiovascular manifestations, its utility in Mendelian CHM has not been previously demonstrated. We tested whether PGD and in vitro fertilization (IVF) technology, including oocyte donation, can identify fertilized eggs affected by HOS for potential embryo selection. Five donor oocytes were fertilized in vitro with sperm from a HOS patient heterozygous for a Glu69ter-TBX5 mutation and then underwent embryo biopsy and genotyping. One carried the Glu69ter-TBX5 mutation; all others had wildtype genotypes. Two wildtype blastocysts were transferred to the mother, and the resulting singleton pregnancy was successfully delivered. Mutational analysis of fetal amniocytes and postpartum umbilical cord blood confirmed PGD. Fetal ultrasonography as well as postpartum electrocardiography and echocardiography also validated accurate prediction of normal skeletal and cardiac phenotypes. We conclude that PGD is an effective reproductive strategy for HOS patients. As more genetic etiologies for CHM are identified, application of PGD as adjunctive therapy to IVF will be increasingly available to prevent transmission of such diseases from affected parents to their children. Clinical application of PGD must balance the benefits of avoiding disease transmission with the medical risks and financial burdens of IVF.