Oral mucositis & oral health related quality of life in women undergoing chemotherapy for breast cancer in Karachi, Pakistan: A multicenter hospital based cross-sectional study

BACKGROUND

Oral mucositis is an inflammatory condition of oral cavity which is a common and serious side effect of cancer treatment. Severe oral mucositis compromises basic functions like eating and swallowing causing malnutrition also affecting overall patient's oral health related quality of life. The aim of the study was to find the frequency of oral mucositis in patients with breast cancer during their chemotherapy, the factors associated with oral mucositis & the overall patient's oral health related quality of life.

METHODS

A cross-sectional study was conducted and a total of 160 women diagnosed with breast cancer, receiving chemotherapy and who had undergone at least one cycle of chemotherapy were recruited from two hospital settings. In-person interviews were done, patients were asked questions about their sociodemographic history, personal habits, oral history and oral findings, breast cancer stage, chemotherapy history and Oral Health Related Quality of Life. Their oral examination was done at the end of the interview to assess presence or absence of oral mucositis, using World Health Organization oral mucositis tool. Oral Health Related Quality of Life was assessed using Oral Health Impact Profile-14 questionnaire.

RESULTS

Our results showed that out of 160 patients 88 (55%) of the breast cancer cases developed oral mucositis during chemotherapy. The mean Oral Health Impact Profile -14 scores in patients with oral mucositis was high 18.36±0.96 showing poor Oral Health Related Quality of Life. Occasional frequency of brushing was significantly associated with oral mucositis (Prevalence ratio:2.26, 95%_CI 1.06-4.84) compared to those patients who brushed once and twice daily. Low level of education showed negative association with oral mucositis (Prevalence ratio:0.52, 95%_CI 0.31-0.88).

CONCLUSION

Our study showed significant positive association of occasional brushing with OM and protective association of low level of education with the development of OM. Emphasis should be given to oral hygiene instructions and dental education to cancer patients in oncology clinics with the prescription of mouth washes, gels and toothpaste to patients to decrease OM during chemotherapy.

Determining the 3-substituted Coumarins inhibitory potential against the HslV protease of E. coli

OBJECTIVE

The growing bacterial resistance towards classical antibiotics demands the development of novel approaches for the effective treatment of potentially fatal bacterial infections in humans. Proteostasis is crucial for the survival of every living cell, as several important physiological functions depend on well-regulated proteostasis. Within bacteria, the regulation of proteostasis relies on AAA+ (Adenosine 5'-triphosphatases associated with diverse cellular activities), ATPases, such as the HslVU complex (heat shock locus gene products U and V), along with other proteases. The HslVU protease/chaperon complex is thought to be the progenitor of the eukaryotic proteasome that regulates proteostasis mostly in prokaryotes. This study aimed to determine the inhibitory potential of 3-substituted coumarin derivatives against Escherichia coli heat shock locus V (HslV) protease.

MATERIALS AND METHODS

In this study, twenty-three derivatives of 3-substituted coumarin were assessed for their inhibitory potential against E. coli HslV protease using both in-vitro and in-silico techniques.

RESULTS

Among all the tested compounds, US-I-64, US-I-66, US-I-67, and US-I-68 displayed notable inhibitory potential against the HslV protease, showing IC50 (half maximal inhibitory concentration) values ranging from 0.2 to 0.73 μM. Additionally, the inhibitory potential of these compounds against the eukaryotic proteasome was also evaluated using a separate in-silico study. It was found that these compounds did not bind with the proteasomal active site, suggesting no apparent side effects of these lead molecules.

CONCLUSIONS

These identified HslV protease inhibitors can be used for the development of novel and safer anti-bacterial drugs.

Author Correction: Inhibitory potential of triazines and hydrazinyl thiazole substituted chromones against the HslVU protease/chaperone complex, a novel drug target

Correction to: European Review for Medical and Pharmacological Sciences 2022; 26 (22): 8567-8575. DOI: 10.26355/eurrev_202211_30392-PMID: 36459037-published online on November 30, 2022. After publication, the authors applied some corrections to the text: - Dr. U. Salar's affiliation has been corrected as follows: Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan. - The values in the row "Binding energy with HsIV (Kcal/mol)" Table I have been corrected as follows: from -8.4 into -9.0; from -8.6 into -9.2; from -8.0 into -8.5 from -8.3 into -8.7. There are amendments to this paper. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/30392.

Inhibitory potential of triazines and hydrazinyl thiazole substituted chromones against the HslVU protease/chaperone complex, a novel drug target

OBJECTIVE

Proteostasis is an important process occurring in all living cells and is highly indispensable for cell survival. The HslVU protease/chaperone complex's critical role in regulating proteostasis to maintain a healthy cellular proteome and its presence in pathogenic microbes made it an important drug target. This study aimed to identify small molecular inhibitors of the HslV protease.

MATERIALS AND METHODS

Herein, a library of small molecules belonging to the triazine and chromone families has been evaluated for their inhibitory potential against the E. coli HslV protease using both in silico and in vitro techniques.

RESULTS

Four compounds, i.e., SHS-II-123a, SHS-II-147a, US-IV-89, and US-IV-92, were identified as potential inhibitors of the HslV protease having IC50 values in the range of 0.1 to 0.32 µM. Additionally, these compounds' drug-likeness and ADMET profiles indicated their compatibility to be considered safer drug candidates.

CONCLUSIONS

To the best of our knowledge, this is the first report on small molecules having inhibitory effects on the HslVU complex. These identified compounds can be efficiently subjected to further investigations to develop novel and safer antimicrobial agents.

Healthcare professionals' perceptions of implementing a decision support intervention for cascade screening for beta-thalassemia in Pakistan

Counselling relatives of individuals with βeta-Thalassaemia Major (β-TM) about cascade screening is the role of field officers (FOs) in the Punjab Thalassaemia Prevention Project (PTPP). This paper presents FOs' views about using a 'decision support intervention for relatives' (DeSIRe) to facilitate informed decision making, and their perception of its implementation and sustainability. Semi-structured qualitative interviews were conducted with nine FOs (June to July 2021) in seven cities in the Punjab province (Lahore, Sheikhupura, Nankana Sahab, Kasur, Gujranwala, Multan, and Faisalabad) following its use in routine clinical practice. Thematic analysis shows that the FOs were overwhelmingly supportive of the DeSIRe, expressing enthusiasm and identifying benefits of its use, both for their own practice and for relatives. They supported the aim of the intervention to enable them to facilitate relatives' decision-making about cascade screening, and advocated its use more widely within the PTPP and the other provinces of Pakistan. Overall, the DeSIRe was valued by the FOs for use in routine practice. These findings suggest the DeSIRe is highly likely to be implemented by healthcare professionals more widely in the PTPP and, therefore, is worth evaluating to prove its efficacy. Further research is needed on the extent to which the DeSIRe could be adapted for use by other healthcare professionals with similar responsibilities in the other provinces of Pakistan, and in other low-middle income countries.

Spectrum of germline pathogenic variants using a targeted next generation sequencing panel and genotype-phenotype correlations in patients with suspected hereditary breast cancer at an academic medical centre in Pakistan

Background

Breast cancer is the most common malignancy in women, affecting over 1.5 million women every year, which accounts for the highest number of cancer-related deaths in women globally.

Hereditary breast cancer (HBC), an important subset of breast cancer, accounts for 5–10% of total cases. However, in Low Middle-Income Countries (LMICs), the population-specific risk of HBC in different ethnicities and the correlation with certain clinical characteristics remain unexplored.

Methods

Retrospective chart review of patients who visited the HBC clinic and proceeded with multi-gene panel testing from May 2017 to April 2020.

Descriptive and inferential statistics were used to analyze clinical characteristics of patients. Fisher’s exact, Pearson’s chi-squared tests and Logistic regression analysis were used for categorical variables and Wilcoxon rank-sum test were used for quantitative variables. For comparison between two independent groups, Mann-Whitney test was performed. Results were considered significant at a p value of < 0.05.

Results

Out of 273 patients, 22% tested positive, 37% had a VUS and 41% had a negative genetic test result. Fifty-five percent of the positive patients had pathogenic variants in either BRCA1 or BRCA2, while the remaining positive results were attributed to other genes. Patients with a positive result had a younger age at diagnosis compared to those having a VUS and a negative result; median age 37.5 years, IQR (Interquartile range) (31.5–48). Additionally, patients with triple negative breast cancer (TNBC) were almost 3 times more likely to have a positive result (OR = 2.79, CI = 1.42–5.48 p = 0.003). Of all patients with positive results, 25% of patients had a negative family history of breast and/or related cancers.

Conclusions

In our HBC clinic, we observed that our rate of positive results is comparable, yet at the higher end of the range which is reported in other populations. The importance of expanded, multi-gene panel testing is highlighted by the fact that almost half of the patients had pathogenic or likely pathogenic variants in genes other than BRCA1/2, and that our test positivity rate would have only been 12.8% if only BRCA1/2 testing was done. As the database expands and protocol-driven referrals are made across the country, our insight about the genetic architecture of HBC in our population will continue to increase.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13053-022-00232-2.

Cascade screening for beta-thalassaemia in Pakistan: relatives' experiences of a decision support intervention in routine practice

Low uptake of cascade screening for βeta-thalassaemia major (β-TM) in the 'Punjab Thalassaemia Prevention Project' (PTPP) in Pakistan led to the development of a 'decision support intervention for relatives' (DeSIRe). This paper presents the experiences of relatives of children with β-TM of the DeSIRe following its use by PTPP field officers (FOs) in routine clinical practice. Fifty-four semi-structured qualitative interviews were conducted (April to June 2021) with relatives in seven cities in the Punjab province (Lahore, Sheikhupura, Nankana Sahab, Kasur, Gujranwala, Multan and Faisalabad). Thematic analysis shows that participants were satisfied with the content of the DeSIRe and its delivery by the FOs in a family meeting. They understood that the main purpose of the DeSIRe was to improve their knowledge of β-TM and its inheritance, and to enable them to make decisions about thalassaemia carrier testing, particularly before marriage. Participants also raised concerns about the stigma of testing positive; however, they believed the DeSIRe was an appropriate intervention, which supported relatives to make informed decisions. Our findings show that the DeSIRe is appropriate for use by healthcare professionals in routine practice in a low-middle income country, and has the potential to facilitate shared decision making about cascade screening for thalassaemia. Further research is needed to prove the efficacy of the DeSIRe.

Cascade screening for beta-thalassemia in Pakistan: development, feasibility and acceptability of a decision support intervention for relatives

The government-funded ‘Punjab Thalassaemia Prevention Project’ (PTPP) in Pakistan includes cascade screening for biological relatives of children with beta-Thalassaemia Major (β-TM). However, there is low uptake of cascade screening. This paper presents the (i) development of a paper-based ‘decision support intervention for relatives’ (DeSIRe) to enable PTPP Field Officers to facilitate informed decision making about carrier testing, and (ii) assessment of the feasibility and acceptability of the DeSIRe. The intervention was developed using the International Patient Decision Aids Standards quality criteria and Ottawa Decision Support Framework. Twelve focus groups were conducted (September and October 2020) to explore the views of healthcare professionals (HCPs) and relatives of children with β-TM, in six cities. The focus groups were attended by 117 participants (60 HCPs and 57 relatives). Thematic analysis showed that the DeSIRe was considered acceptable for supporting relatives to make informed decisions about cascade screening, and potentially feasible for use in clinical practice. Suggestions for changing some words, the structure and adding information about how carrier testing relates to consanguineous marriages will enable further development of the DeSIRe. Participants generally welcomed the DeSIRe; however, they highlighted the perceived need to use more directive language, hence showed a cultural preference for directive genetic counselling. The findings highlight challenges for researchers using western theories, frameworks, policies and clinical guidelines to develop decision support interventions for implementation more globally. Future research is needed to evaluate the use of the DeSIRe in routine practice and whether it enables relatives to make informed decisions.

Decision making on antenatal screening results: A comparative Q-method study of women from two Chinese cities

Background

Although an integral part of ethical and quality health care, little is known about the informed decision making of Chinese women with different socioeconomic backgrounds within the context of antenatal testing.

Methods

To explore women's viewpoints on informed decision making regarding antenatal screening, a Q‐methodology study that combines both quantitative factor analysis and interviews was conducted between June 2016 and February 2017 in Shanghai and Duyun. A total of 169 women (84 Shanghai and 85 Duyun) participated in the study of 41 ranked statements along a Q‐sorting grid.

Results

Using by‐person factor analysis, five distinct viewpoints are identified: (a) choice is shared with the partner/husband, but the mother has the right to make the final decision; (b) having antenatal tests is not about choice but about a mother's responsibility; (c) choice is a shared decision led primarily by the partner/husband and secondarily by the doctors; (d) choice should be made using the advice of doctors, but the decision should be made with the partner/husband; and (e) choice is a responsibility shared with the partner, family and doctors.

Conclusions

The study reveals that women with better education and higher incomes demonstrate more autonomy than those with less education. The nuclear family clearly emerges as the main decision makers in health‐care services in China.

Patient and Public Contribution

The 169 participants shared their views and stories for at least an hour. They were debriefed after the interviews and contributed their thoughts on our study design and interpretation of the data.

Autonomous decision-making for antenatal screening in Pakistan: views held by women, men and health professionals in a low-middle income country

Prenatal genetic technologies now are being implemented in LMICs, and while there is much research on the ethical, legal and social implications of such technologies in Western countries, there is a paucity of such research in LMICs, which have diverse cultural, religious, political, financial and health service contexts. This study aimed to explore views about women's autonomous decision-making for antenatal screening held by women, men and healthcare professionals (HCPs) in Pakistan. A Q-methodology study was conducted during June 2016 to January 2018 in Lahore, Pakistan. A total of 137 participants (60 women, 57 men, 20 HCPs) rank-ordered 41 statements. Following by-person factor analysis, four distinct viewpoints were identified. Three of these represent views held by women and men only: autonomous decision-making requires directive advice from doctors; autonomous decision-making requires the husband's involvement, where independent decision-making by the woman is considered culturally inappropriate; and opting for antenatal screening is a foregone decision. One contrasting viewpoint represents predominantly HCPs: autonomous decision-making is the couple's responsibility. These findings highlight that Western approaches to facilitating women's autonomy for antenatal screening are unlikely to be suitable for use in Pakistan. Instead, culturally appropriate practice guidelines are needed in LMICs to enable HCPs to adopt shared decision-making approaches in a way that enables them to facilitate active and joint decision-making by couples, while ensuring women exercise their autonomy.

Attitudes towards non-invasive prenatal diagnosis among obstetricians in Pakistan, a developing, Islamic country

OBJECTIVES

Stakeholders' views are essential for informing implementation strategies for non-invasive prenatal testing (NIPT). Little is known about such views in developing countries. We explored attitudes towards NIPT among obstetricians in Pakistan, a developing, Islamic country.

METHODS

A 35-item questionnaire was distributed and collected at eight events (a national conference and seven workshops in five cities) for obstetric professionals on advances in fetal medicine.

RESULTS

Responses from 113 obstetrician show positive attitudes towards implementation of NIPT: 95% agreed prevention of genetic conditions was a necessity, and 97% agreed public hospitals should provide prenatal screening tests. However, participants also agreed the availability of NIPT would increase social pressure on women to have prenatal screening tests and to terminate an affected pregnancy (53% and 63%, respectively). Most participants would not offer NIPT for sex determination (55%), although 31% would. The most valued aspects of NIPT were its safety, followed by its utility and then accuracy.

CONCLUSION

Participants generally supported the implementation of NIPT but raised concerns about social implications. Therefore, national policy is needed to regulate the implementation of NIPT, and pretest information and post-test genetic counselling are needed to mitigate social pressure and support parents to make informed decisions. © 2017 John Wiley & Sons, Ltd.

Identification of mutations in SLC24A4, encoding a potassium-dependent sodium/calcium exchanger, as a cause of amelogenesis imperfecta

A combination of autozygosity mapping and exome sequencing identified a null mutation in SLC24A4 in a family with hypomineralized amelogenesis imperfect a (AI), a condition in which tooth enamel formation fails. SLC24A4 encodes a calcium transporter upregulated in ameloblasts during the maturation stage of amelogenesis. Screening of further AI families identified a missense mutation in the ion-binding site of SLC24A4 expected to severely diminish or abolish the ion transport function of the protein. Furthermore, examination of previously generated Slc24a4 null mice identified a severe defect in tooth enamel that reflects impaired amelogenesis. These findings support a key role for SLC24A4 in calcium transport during enamel formation.

Molecular confirmation of the causes of inherited visual impairment in Northern Pakistan

Families with inherited visual impairment were identified and examined from January 2000 to December 2005 and given a clinical diagnosis. Known genes and loci were screened for mutations or linkage at Institute of Ophthalmology and Neurosciences, University of Leeds, in order to provide molecular confirmation. Inherited retinal disease was the most common cause of inherited visual impairment in 38 of 57 families (66.6%) with Leber's congenital amaurosis, rod-cone dystrophy and cone-rod dystrophy being the most common diagnoses in 22, 8 and 3 families respectively. Anterior segment dysgenesis was diagnosed in 8 families (14%). Mutations in known genes or linkage to known loci were identified in 23 of 57 families (40%). All families had molecular confirmation of autosomal recessive inheritance or a pedigree consistent with this mode of inheritance, with evidence of first-cousin marriage. Knowledge of carrier status and genetic counseling may allow families to make an informed decision regarding marriage, and thus begin to plan a way of reducing the incidence of inherited visual impairment.

Mutations in the beta propeller WDR72 cause autosomal-recessive hypomaturation amelogenesis imperfecta

Healthy dental enamel is the hardest and most highly mineralized human tissue. Though acellular, nonvital, and without capacity for turnover or repair, it can nevertheless last a lifetime. Amelogenesis imperfecta (AI) is a collective term for failure of normal enamel development, covering diverse clinical phenotypes that typically show Mendelian inheritance patterns. One subset, known as hypomaturation AI, is characterised by near-normal volumes of organic enamel matrix but with weak, creamy-brown opaque enamel that fails prematurely after tooth eruption. Mutations in genes critical to enamel matrix formation have been documented, but current understanding of other key events in enamel biomineralization is limited. We investigated autosomal-recessive hypomaturation AI in a consanguineous Pakistani family. A whole-genome SNP autozygosity screen identified a locus on chromosome 15q21.3. Sequencing candidate genes revealed a point mutation in the poorly characterized WDR72 gene. Screening of WDR72 in a panel of nine additional hypomaturation AI families revealed the same mutation in a second, apparently unrelated, Pakistani family and two further nonsense mutations in Omani families. Immunohistochemistry confirmed intracellular localization in maturation-stage ameloblasts. WDR72 function is unknown, but as a putative β propeller is expected to be a scaffold for protein-protein interactions. The nearest homolog, WDR7, is involved in vesicle mobilization and Ca²⁺-dependent exocytosis at synapses. Vesicle trafficking is important in maturation-stage ameloblasts with respect to secretion into immature enamel and removal of cleaved enamel matrix proteins via endocytosis. This raises the intriguing possibility that WDR72 is critical to ameloblast vesicle turnover during enamel maturation.

Genetic and epigenetic analysis of recurrent hydatidiform mole

Familial biparental hydatidiform mole (FBHM) is a maternal-effect autosomal recessive disorder in which recurrent pregnancy failure with molar degeneration occurs. The phenotype mimics molar pregnancy due to androgenesis, despite the normal genetic makeup of the conceptus. FBHM appears to result from a failure to establish correct maternal epigenetic identity at imprinted loci during oogenesis. Several women affected with FBHM have previously been shown to have biallelic mutations in the NLRP7 gene (NALP7). Here, we present the results of epigenetic and mutational analysis on FBHM patients from 11 families, 10 of them novel. We demonstrate a methylation defect at imprinted loci in tissue from four new FBHM cases. Biallelic NLRP7 mutations, including eight previously undescribed mutations, were found in all but one family. These results indicate for the first time that maternal imprints at some loci may be correctly specified in FBHM conceptions, since differential methylation of SGCE/PEG10 was preserved in all four cases.

Loss of the metalloprotease ADAM9 leads to cone-rod dystrophy in humans and retinal degeneration in mice

Cone-rod dystrophy (CRD) is an inherited progressive retinal dystrophy affecting the function of cone and rod photoreceptors. By autozygosity mapping, we identified null mutations in the ADAM metallopeptidase domain 9 (ADAM9) gene in four consanguineous families with recessively inherited early-onset CRD. We also found reduced photoreceptor responses in Adam9 knockout mice, previously reported to be asymptomatic. In 12-month-old knockout mice, photoreceptors appear normal, but the apical processes of the retinal pigment epithelium (RPE) cells are disorganized and contact between photoreceptor outer segments (POSs) and the RPE apical surface is compromised. In 20-month-old mice, there is clear evidence of progressive retinal degeneration with disorganized POS and thinning of the outer nuclear layer (ONL) in addition to the anomaly at the POS-RPE junction. RPE basal deposits and macrophages were also apparent in older mice. These findings therefore not only identify ADAM9 as a CRD gene but also identify a form of pathology wherein retinal disease first manifests at the POS-RPE junction.

A missense mutation in the nuclear localization signal sequence of CERKL (p.R106S) causes autosomal recessive retinal degeneration

PURPOSE

To investigate the genetic basis of autosomal recessive retinal degeneration in a large consanguineous family from Pakistan.

METHODS

Ophthalmic examinations were conducted on family members to establish their diagnosis. Genomic DNA extracted from peripheral blood was used for homozygosity mapping to discover the chromosomal region that harbors the defective gene. Direct sequence analysis and restriction enzyme digestion were used to identify and confirm the defect in the gene.

RESULTS

There were three affected siblings in the family, each with limited peripheral vision and impaired visual acuity. We established linkage to a region on chromosome 2 that encompasses the RP26 locus. Upon sequencing the ceramide kinase-like (CERKL) gene, which is mutated in the original RP26 family, we identified a C>A transversion in exon 2 (c.316C>A) that substitutes an arginine residue with a serine (p.R106S) in the conserved nuclear localization signal sequence (KLKRR) of the protein. This mutation segregated with retinal degeneration in the Pakistani family and was not observed in the DNA of 174 ethnically matched unaffected controls.

CONCLUSIONS

This is the third reported mutation in CERKL causing retinal degeneration but is the first report to show that a single amino acid change in CERKL, rather than a null mutation, can cause retinal disease. Although the function of CERKL is still unknown, the mutation described herein confirms that the nuclear localization signal sequence is important in the physiologic function of the protein.

Prenatal diagnosis of beta-thalassaemia by chorionic villous sampling

OBJECTIVE

To establish intrauterine diagnosis of thalassaemia major in couples with thalassaemia trait by chorionic villous sampling.

METHODS

A total of 60 couples with children suffering from transfusion dependent beta-thalassaemia or couples who were known carriers of beta-thalassaemia were included in this study. The standard procedure was followed for the collection of samples which was finally transferred in appropriate medium to Armed Forces Institute of Pathology Rawalpindi for detection of thalassaemia mutation.

RESULTS

After DNA analysis of the submitted samples, no thalassaemia mutation was detected in the foetus in 24 cases. In 8 cases foetus were heterozygote for thalassaemia having a single mutation. In 28 cases, foetus were homozygous for beta-thalassaemia.

CONCLUSION

Appropriate and extensive screening, accurate detection and counseling of at risk couples, along with antenatal diagnosis is a promising strategy for the reduction of mortality and morbidity from thalassaemia in countries where it is prevalent. Based on these results, it can be concluded that prenatal diagnosis of beta-thalassaemia for prevention can be done using chorionic villous sampling.

Mutations in LCA5, encoding the ciliary protein lebercilin, cause Leber congenital amaurosis

Leber congenital amaurosis (LCA) causes blindness or severe visual impairment at or within a few months of birth. Here we show, using homozygosity mapping, that the LCA5 gene on chromosome 6q14, which encodes the previously unknown ciliary protein lebercilin, is associated with this disease. We detected homozygous nonsense and frameshift mutations in LCA5 in five families affected with LCA. In a sixth family, the LCA5 transcript was completely absent. LCA5 is expressed widely throughout development, although the phenotype in affected individuals is limited to the eye. Lebercilin localizes to the connecting cilia of photoreceptors and to the microtubules, centrioles and primary cilia of cultured mammalian cells. Using tandem affinity purification, we identified 24 proteins that link lebercilin to centrosomal and ciliary functions. Members of this interactome represent candidate genes for LCA and other ciliopathies. Our findings emphasize the emerging role of disrupted ciliary processes in the molecular pathogenesis of LCA.

Regional and ethnic distribution of beta thalassemia mutations and effect of consanguinity in patients referred for prenatal diagnosis

OBJECTIVE

To determine the regional and ethnic distribution of beta thalassemia mutation and the effect of consanguinity in patients referred for prenatal diagnosis of beta b-thalassemia and to target the high risk population for screening.

DESIGN

Cross-sectional, analytical study.

PLACE AND DURATION OF STUDY

The study was conducted in Gentec Laboratory, Lahore, from January 2001 to December 2005.

PATIENTS AND METHODS

A total of 499 couples were referred to Gentec Lab., Lahore, from all over Pakistan for prenatal diagnosis of b-thalassemia. After counseling, chorionic villus sampling was done between 10-16 weeks of gestation. DNA analysis was done by Amplification Refractory Mutation System (ARMS) for type of mutation in the Armed Forces Institute of Pathology, Rawalpindi. Ethnicity, race and consanguineous relationship of parents was determined.

RESULTS

b-thalassemia was prevalent in Punjabis (60.7%) followed by Saraikees (25.5%). Castewise it was most frequent in Rajputs followed by Jatts, Arain, Sheikhs and Pathans. 56.7% of the couples were first cousins and 19.8% were relatives. The commonest mutations were Frameshift 8-9 (Fr8-9) 33.5%, Intervening Sequence 1-5 (IVS 1-5) 17.2%, Fr4142 - 8%, IVS 1-1 - 5.2%, Deletion 619 (Del 619) 4.2% and Codon 5 (Cd 5) - 4.2%. In samples sent for analysis, 53.1% turned out to be carriers (trait), 25.3% were diseased (thalassemia major) and 21.6% were normal. P-value of all results was less than 0.001.

CONCLUSION

In this series, the highest frequency was found in Punjabi Rajputs. The commonest mutation was Fr 8-9. Most parents were first cousins. Premarital thalassemia carrier testing can effectively reduce the disease.

MORM syndrome (mental retardation, truncal obesity, retinal dystrophy and micropenis), a new autosomal recessive disorder, links to 9q34

A consanguineous pedigree is described where 14 individuals are affected with a novel autosomal recessive disorder, which causes static moderate mental retardation, truncal obesity, a congenital nonprogressive retinal dystrophy and micropenis in males. We have tentatively named this condition MORM syndrome. It shows similarities to Bardet-Biedl syndrome and Cohen syndrome, but can be distinguished by clinical features; the age of onset and nonprogressive nature of the visual impairment, the lack of characteristic facies, skin or gingival infection, microcephaly, 'mottled retina', polydactyly and small penis without testicular anomalies. Furthermore, linkage to the known Bardet-Biedl (BBS1-8) and Cohen syndrome loci was excluded. Autozygosity mapping identified a single homozygous subtelomeric region shared by all affecteds on chromosome 9q34.3, with a maximum LOD score of 5.64. We believe this to be the first example of the identification of a subtelomeric recessive locus by autozygosity mapping.

A centrosomal mechanism involving CDK5RAP2 and CENPJ controls brain size

Autosomal recessive primary microcephaly is a potential model in which to research genes involved in human brain growth. We show that two forms of the disorder result from homozygous mutations in the genes CDK5RAP2 and CENPJ. We found neuroepithelial expression of the genes during prenatal neurogenesis and protein localization to the spindle poles of mitotic cells, suggesting that a centrosomal mechanism controls neuron number in the developing mammalian brain.

Mutations in microcephalin cause aberrant regulation of chromosome condensation

Microcephalin (MCPH1) is a gene mutated in primary microcephaly, an autosomal recessive neurodevelopmental disorder in which there is a marked reduction in brain size. PCC syndrome is a recently described disorder of microcephaly, short stature, and misregulated chromosome condensation. Here, we report the finding that MCPH1 primary microcephaly and PCC syndrome are allelic disorders, both having mutations in the MCPH1 gene. The two conditions share a common cellular phenotype of premature chromosome condensation in the early G2 phase of the cell cycle, which, therefore, appears to be a useful diagnostic marker for individuals with MCPH1 gene mutations. We demonstrate that an siRNA-mediated depletion of MCPH1 is sufficient to reproduce this phenotype and also show that MCPH1-deficient cells exhibit delayed decondensation postmitosis. These findings implicate microcephalin as a novel regulator of chromosome condensation and link the apparently disparate fields of neurogenesis and chromosome biology. Further characterization of MCPH1 is thus likely to lead to fundamental insights into both the regulation of chromosome condensation and neurodevelopment.

Protein-truncating mutations in ASPM cause variable reduction in brain size

Mutations in the ASPM gene at the MCPH5 locus are expected to be the most common cause of human autosomal recessive primary microcephaly (MCPH), a condition in which there is a failure of normal fetal brain development, resulting in congenital microcephaly and mental retardation. We have performed the first comprehensive mutation screen of the 10.4-kb ASPM gene, identifying all 19 mutations in a cohort of 23 consanguineous families. Mutations occurred throughout the ASPM gene and were all predicted to be protein truncating. Phenotypic variation in the 51 affected individuals occurred in the degree of microcephaly (5-11 SDs below normal) and of mental retardation (mild to severe) but appeared independent of mutation position.

Identification of a locus (LCA9) for Leber's congenital amaurosis on chromosome 1p36

Leber's congenital amaurosis (LCA) is the most common cause of inherited childhood blindness and is characterised by severe retinal degeneration at or shortly after birth. We have identified a new locus, LCA9, on chromosome 1p36, at which the disease segregates in a single consanguineous Pakistani family. Following a whole genome linkage search, an autozygous region of 10 cM was identified between the markers D1S1612 and D1S228. Multipoint linkage analysis generated a lod score of 4.4, strongly supporting linkage to this region. The critical disease interval contains at least 5.7 Mb of DNA and around 50 distinct genes. One of these, retinoid binding protein 7 (RBP7), was screened for mutations in the family, but none was found.

Autosomal recessive primary microcephaly: an analysis of locus heterogeneity and phenotypic variation

BACKGROUND AND OBJECTIVES

Locus heterogeneity is well established in autosomal recessive primary microcephaly (MCPH) and to date five loci have been mapped. However, the relative contributions of these loci have not been assessed and genotype-phenotype correlations have not been investigated.

DESIGN

A study population of 56 consanguineous families resident in or originating from northern Pakistan was ascertained and assessed by the authors. A panel of microsatellite markers spanning each of the MCPH loci was designed, against which the families were genotyped.

RESULTS

The head circumference of the 131 affected subjects ranged from 4 to 14 SD below the mean, but there was little intrafamilial variation among affecteds (+/- 1 SD). MCPH5 was the most prevalent, with 24/56 families consistent with linkage; 2/56 families were compatible with linkage to MCPH1, 10/56 to MCPH2, 2/56 to MCPH3, none to MCPH4, and 18/56 did not segregate with any of the loci.

CONCLUSIONS

MCPH5 is the most common locus in this population. On clinical grounds alone, the phenotype of families linked to each MCPH locus could not be distinguished. We have also shown that further MCPH loci await discovery with a number of families as yet unlinked.

Identification of microcephalin, a protein implicated in determining the size of the human brain

Primary microcephaly (MIM 251200) is an autosomal recessive neurodevelopmental condition in which there is a global reduction in cerebral cortex volume, to a size comparable with that of early hominids. We previously mapped the MCPH1 locus, for primary microcephaly, to chromosome 8p23, and here we report that a gene within this interval, encoding a BRCA1 C-terminal domain-containing protein, is mutated in MCPH1 families sharing an ancestral 8p23 haplotype. This gene, microcephalin, is expressed in the developing cerebral cortex of the fetal brain. Further study of this and related genes may provide important new insights into neocortical development and evolution.

A fifth locus for primary autosomal recessive microcephaly maps to chromosome 1q31

Primary microcephaly is a genetic disorder in which an affected individual has a head circumference >3 SDs below the age- and sex-related mean. A small but apparently normally formed brain is the reason for the reduced head circumference, and, probably because of this, all affected individuals are mentally retarded. The condition is genetically heterogeneous, and four loci have already been identified. We now report a fifth locus, MCPH5, which is an 8-cM region mapping to chromosome 1q31, defined by the markers GATA135F02 and D1S1678.

The second locus for autosomal recessive primary microcephaly (MCPH2) maps to chromosome 19q13.1-13.2

Primary microcephaly is a clinical diagnosis made when an individual has a head circumference of greater than 3 standard deviations below the age and sex matched population mean, mental retardation but without other associated malformations and no apparent aetiology. The majority of cases of primary microcephaly exhibit an autosomal recessive mode of inheritance. We now demonstrate the genetic heterogeneity of this condition with the identification of a second primary microcephaly locus (MCPH2) on chromosome 19q13.1-13.2 in two multi-affected consanguineous families. The minimum critical region containing the MCPH2 locus is defined by the polymorphic markers D19S416 and D19S420 spanning a region of approximately 7.6 cM.

Down's syndrome: prospects for prevention by antenatal diagnosis

The results of a prospective study on cytogenetic analysis of Chorionic Villus Samples (CVS) taken in early pregnancy (after 10 weeks) from pregnant ladies aged between 22 and 50 years are being presented.

OBJECTIVE

To find out the prevalence of chromosomal defects with advancing age of the mother.

SETTING

Department of Medical Genetics, Armed Forces Institute of Pathology, Rawalpindi.

METHODS

A total of 48 samples have been studied. Ten patients were above the age of 35 years and 38 were below the age of 35 years. Chorionic villus samples were obtained after 10th week of pregnancy through transabdominal approach. Cytogenetic cultures were set up both by the direct and routine methods.

RESULTS

Three out of the seven samples taken from expecting mothers aged above 35 and one culture from a patient aged less than 35, showed trisomy 21.

CONCLUSION

This study highlights the fact that incidence of chromosomal aberrations and the Down's syndrome in particular, increases with the advancing maternal age. Prenatal studies can therefore be utilized to decrease the incidence of various chromosomal abnormalities.

Primary autosomal recessive microcephaly (MCPH1) maps to chromosome 8p22-pter

Primary (or "true") microcephaly is inherited as an autosomal recessive trait and is thought to be genetically heterogeneous. Using autozygosity mapping, we have identified a genetic locus (MCPH1) for primary microcephaly, at chromosome 8p22-pter, in two consanguineous families of Pakistani origin. Our results indicate that the gene lies within a 13-cM region between the markers D8S1824 and D8S1825 (maximum multipoint LOD score of 8.1 at D8S277). In addition, we have demonstrated the genetic heterogeneity of this condition by analyzing a total of nine consanguineous families with primary microcephaly.