Research Article | Open Access
Ghazanfar Ali, Sadia, Jia Nee Foo, Abdul Nasir, Chu-Hua Chang, Elaine GuoYan Chew, Zahid Latif, Zahid Azeem, Syeda Ain-ul-Batool, Syed Akif Raza Kazmi, Naheed Bashir Awan, Abdul Hameed Khan, Fazal-Ur- Rehman, Madiha Khalid, Abdul Wali, Samina Sarwar, Wasim Akhtar, Ansar Ahmed Abbasi, Rameez Nisar, "Identification of a Novel Homozygous Missense (c.443A>T:p.N148I) Mutation in BBS2 in a Kashmiri Family with Bardet-Biedl Syndrome", BioMed Research International, vol. 2021, Article ID 6626015, 9 pages, 2021. https://doi.org/10.1155/2021/6626015
Identification of a Novel Homozygous Missense (c.443A>T:p.N148I) Mutation in BBS2 in a Kashmiri Family with Bardet-Biedl Syndrome
Background. Bardet-Biedl syndrome (BBS) is a rare autosomal recessive inherited disorder with distinctive clinical feature such as obesity, degeneration of retina, polydactyly, and renal abnormalities. The study was aimed at finding out the disease-causing variant/s in patients exhibiting clinical features of BBS. Methods. The identification of disease-causing variant was done by using whole exome sequencing on Illumina HiSeq 4000 platform involving the SeqCap EZ Exome v3 kit (Roche NimbleGen). The identified variant was further validated by Sanger sequencing. Results. WES revealed a novel homozygous missense mutation (NM_031885: c.443A>T:p.N148I) in exon 3 of the BBS2 gene. Sanger sequencing confirmed this variant as homozygous in both affected subjects and heterozygous in obligate parents, demonstrating autosomal recessive inheritance pattern. To the best of our knowledge, this variant was not present in literature and all publically available databases. The candidate variant is predicted to be pathogenic by a set of in-silico softwares. Conclusion. Clinical and genetic spectrum of BBS and BBS-like disorders is not completely defined in the Pakistani as well as in Kashmiri population. Therefore, more comprehensive genetic studies are required to gain insights into genotype-phenotype associations to facilitate carrier screening and genetic counseling of families with such disorders.
Bardet-Biedl syndrome (BBS; OMIM 209900) is a sporadic and genetically heterogeneous developmental syndrome. Primary clinical features of the syndrome include retinal degeneration, polydactyly, hypogonadism, severe kidney problems, and mental retardation along with obesity. Other secondary features associated with BBS are T2DM (type 2 diabetes mellitus), cardiovascular problems, hepatic diseases, hypothyroidism, and abnormal tooth development. The proposed clinical diagnosis of BBS is based on the presence of four major signs or three major and two minor ones. It is stated that BBS patients have insulin resistance that causes impairments in glucose metabolism and insulin sensitivity which subsequently leads to type 2 diabetes [1–4].
The prevalence of BBS in populations where the consanguineous marriages are low is relatively less, like in the population of Northern Europe and North America which ranges between 1/100,000 and 1/160,000, respectively, and in Tunisia which has been estimated at 1/156,000 . However, it is more common in Kuwaiti Bedouins (1/13,500), the Faroe Islands (1/3,700), and Newfoundland (1/17,000) [6, 7]. These prevalence variations are the result of multiple reasons such as consanguinity, which is a social custom in nations such as Pakistan, Iran, Kuwait, and Middle East. The worldwide comprehensive epidemiological data is very less regarding BBS; even the Ashkenazi Jews, being apparently the most genetically studied founder population, have also not yet been exposed regarding BBS. So it is crucial to indicate that several of the document frequencies were not tailored to molecular investigations; consequently, the available number should be treated with care. Till now, very few cases of BBS have been documented in Asia, South America, Africa, and Eastern Europe, and an inclusive study remains to be done in these populations [8, 9].
To date, 21 BBS loci (BBS1-C8or f37/BBS21) (Table 1) have been implicated for BBS whose mutations would explain around 80.0% of affected patients [10, 11]. The study presented here was aimed at determining the clinical and genetic basis of BBS in two patients from a consanguineous Kashmiri family using whole exome screening, to broaden our understanding of spectrum, nature, and molecular basis of BBS in the Kashmiri population.
The state of Azad Jammu and Kashmir (AJ&K) is a bordering region between India and Pakistan; particularly, it is in the northeast of Pakistan and a relatively less developed region. There are no data available that could represent an inclusive picture of epidemiological studies of genetic diseases prevalent in the state. Therefore, further investigations are required to translate this knowledge for making proper clinical services to this kind of inherited disorders.
2.1. Ethics Statement
This study was permitted by the ethical committee/institutional review board of University of Azad Jammu and Kashmir Muzaffarabad. Written informed consent was obtained from the legal guardians of the affected subjects and also from the normal adults who participated in this study for the genetic testing and publication of photographs. After a detailed interview from the elders of the patients, the pedigree was built by using a method presented by Bennett et al. . The pedigree of the family provided a significant indication of autosomal recessive inheritance pattern.
2.2. Genomic DNA Extraction and Whole Exome Sequencing
In order to investigate the disease-causing gene/s, peripheral blood samples were collected from both patients and clinically healthy subjects of the family. Genomic DNA extraction was done using phenol chloroform method . For whole exome sequencing, we selected a clearly affected male (IV-3). Library enrichment for whole exome sequencing was conducted using SeqCap EZ Exome v3 kit (Roche NimbleGen). After that, enriched samples were sequenced by using an Illumina HiSeq 4000 (Illumina, San Diego, CA, USA). The average mean depth of the sequencing reads was kept up to 36x, and each read from the target region was covered ~94%.
2.3. Variant Calling
After the removal of adaptors and low-quality reads, the qualified raw fastq file was processed as per the recommendations of (GATK) “Best Practices for Germline SNP & Indel Discovery.” The clean sequences were mapped to UCSC Genome Browser hg19 by using Burrows–Wheeler Aligner (BWA-MEM v0.7.12), and subsequently, PCR duplicates were removed by using Picard v1.141. Finally, variant calling was done by using the GATK v2 Unified Genotyper.
2.4. Variant Annotation and Prioritization
All noncoding, synonymous variants with minor allele frequency in publicly available databases including Exome Aggregation Consortium (ExAC) (http://exac.broadinstitute.org/), 1000 Genomes, and Genome Aggregation Database (gnomAD) (https://gnomad.broadinstitute.org/) were excluded from the analysis. Only splice site, synonymous splice site variants, nonsense, nonsynonymous, indels that affect coding regions of gene were used for interpretation. Furthermore, the potential deleterious effect of the pathogenic variant on the structure and function of the protein was evaluated by using a set of in silico algorithms: SIFT (http://sift.jcvi.org/), PolyPhen2 (http://genetics.bwh.harvard.edu/pph2/), Mutation Taser (http://www.mutationtaster.org/), FATHMM (http://fathmm.biocompute.org.uk/index.html), Likelihood Ratio Test (LRT), and Condel .
2.5. Sanger Validation
The validation of expected candidate variant and extended segregation of candidate variants in all family members was done through Sanger sequencing.
2.6. 3D Modeling of the Protein
The amino acid sequence of BBS2 protein was retrieved from the NCBI database (http://www.ncbi.nlm.nih.gov/), imported to pBlast search against Protein Data Bank (PDB). Chaetomium thermophilum (PDB: 6RXT) was used as a template for modeling of the three-dimensional structure of wild and mutant BBS2 protein using I-Tasser software (Iterative Threading ASSEmbly Refinement) [15, 16]. Structural models were visualized by PyMOL (http://www.pymol.org). NCBI HomoloGene (http://www.ncbi. http://nlm.gov/Homologene/) was used to analyse the amino acid conservation among different orthologs.
3.1. Clinical Report
In this study, a consanguineous Kashmiri family exhibiting clinical features of BBS was recruited from district Bagh Azad Jammu and Kashmir. The diagnosis was ascertained by following a previously established criteria for BBS . The family comprises two affected subjects IV-2 and IV-3, and both were born from clinically normal parents who were first cousins by relation (Figure 1(a)). The patients exhibited obesity, renal problems, intellectual disability (ID), and postaxial polydactyly of hands and feet as a common phenotype. However, extra digits were operated in both patients at the time of the study (Figures 1(b)–1(g)). Patient IV-2 was reported with more severe ID than her brother (IV-3). These gross clinical investigations confirmed the diagnosis of BBS syndrome in both subjects. The affected male (IV-3) was also reported to have hypogonadism. Detailed clinical phenotypes are summarized in (Table 2).
All primary and secondary features investigated in both affected subjected are summarized in Table 2.
3.2. Molecular Findings
After exclusion of all the noncoding, nonsynonymous, and rare variants with across all assessed populations including 1000 Genomes, ExAC, and gnomAD, we got 21,664 variants in individual IV-3. All these filtration steps are mentioned in Figure 2. Then, based on the information collected from the previous literature (OMIM/PubMed) and pedigree illustration, we initially focused on homozygous variants; there were a total of 20 homozygous variants, and 3 of the variants were predicted to be damaging by SIFT and PolyPhen2 (Figure 2, Table 3). We then focused on the missense BBS2 variant (NM_031885: c.443A>T:p.N148I) as the gene has been reported to be involved in BBS. The substitution of g16:56545099T>A occurs in exon 3 of the BBS2 gene, leading to the N148I amino change. Sanger validation was done, and the variant was perfectly segregated among the individuals. Both patients were homozygous (Figure 3(c)), and their obligate parents were heterozygous (Figure 3(b)) for the mutation. However, the rest of the individuals were either heterozygous carrier or homozygous normal (Figure 3(a)).
This variant has not been reported before in the literature and also in any publicly available database. The variant was predicted to be potentially pathogenic by a set of other prediction algorithms as mentioned above.
In this study, by using whole exome sequencing, we found a novel homozygous missense variant in the BBS2 gene in a Kashmiri family. In addition, we also revealed WES combined with Sanger sequencing can be an effective strategy for molecular genetic diagnosis of BBS-like syndrome. BBS is a ciliopathy disorder that involves various body systems and mostly follows an autosomal recessive inheritance pattern; however, triallelic inheritance is also reported as a possible mechanism by some studies [18–20]. There are 21 genes that are associated with BBS so far; among those, BBS1 and BBS10 are mostly reported from North America and Europe, respectively, whereas BBS2, BBS4, BBS5, and BBS12 are more prevalent in the Middle East and North Africa [11, 21, 22]. Based on previous and our current study, only eight BBS mutated genes (BBS1 (OMIM #209901) , BBS2 (OMIM #606151), BBS3/ARL6 (OMIM #608845), BBS5 (OMIM #603650) , BBS8/TTC8 (OMIM #608132) [25, 26], BBS9 (OMIM #615986) [9, 27], BBS10 (OMIM #610148) [28–30], and BBS12 (OMIM #610683))  have been reported in the Pakistani population.
This study focuses on a consanguineous Kashmiri family having two affected individuals, one male (IV-3) and one female (IV-2) (Figure 1(a)). Both affected individuals exhibit established major symptoms of BBS, including obesity, retinitis pigmentosa, renal abnormalities, polydactyly, and learning disabilities. Other minor features and intrafamilial phenotypic variations were also noted among the affected individuals, like the affected female (IV-2) displayed more significant intellectual disability compared to her brother (IV-3). Bilateral postaxial polydactyly of both fingers and toes was identified upon clinical investigation in individual IV-2. However, the affected male (IV-3) has the only polydactyly of fingers. All these interfamilial and intrafamilial phenotypic variations are well described in BBS by previous studies as well [8, 32, 33].
WES revealed a novel homozygous missense variant (NM_031885: c.443A>T:p.N148I) in exon 3 of the BBS2 gene. The position of the amino acid (N148) is highly conserved across different species (Figure 3(d)), and substitution is predicted to be damaging by in-silico analysis. This mutation was not present in any public database including dbSNP, 1000 Genomes, and ExAC. 3D protein modeling also indicated that the amide Asn residue in the mutant is replaced by Ile residue. The residue at position 148 in wild and mutant type is present at the loop region (Figures 4(a) and 4(b)). The mutation of polar amide side chain residue by nonpolar side chain caused a shortage of β-sheet in the nearby network as shown in Figure 4(d). As a consequence of this different, nature of amino acids and possibly different surface area may alter the function of the protein. The key function of the BBS genes is that they are involved in IFT (intraflagellar transport) and ciliary function. Seven genes (BBS1, BBS2, BBS4, BBS5, BBS7, BBS8, and BBS9) are involved in the formation of the BBSome complex, and BBS6, BBS10, and BBS12 encode protein for the BBS chaperone complex that has a significant role in the maintenance and regulation of the BBSome [11, 34]. Mutations in BBS2 genes are harmful because BBS2 directly interacts with BBS7 and BBS9 to form the core complex that is vital for complete formation of the BBSome and ciliogenesis [1, 35].
Previous studies have reported that the BBS2 gene is the third most frequent BBS gene to harbor mutational load (12.0%) after BBS10 (20.0%) and BBS1 (23.0%) [36, 37]. The cytogenetic location of the BBS2 gene is on chromosome 16q21 and has 18 coding exons that encode 721 amino acid protein. There is a 45-amino acid coiled region in between exons 9 and 10, and this is flanked by peptide chain regions on both sides .
Although genetic studies have reported a total of 81 mutations including 49 missense/nonsense (HGMD, accessed on 30.12.2020) in the BB2 gene, only one mutation has been reported in the Pakistani population so far. This variant (Arg413Ter) was stated by Kordestani et al. in an annual meeting abstract in 2006 , and no detailed clinical information is provided in the abstract.
In conclusion, the present study reported a second novel missense c.443A>T:p.N148I mutation in the BBS2 gene in a Kashmiri family from Pakistani origin. Furthermore, bioinformatics prediction and protein modeling confirmed the deleterious consequences of the identified variant on the BBS2 protein structure. These results can be valuable in the future for more efficient analysis, genetic counseling, and prenatal diagnosis and also for population-specific screening.
The data supporting the findings of this study will be available from the corresponding author upon request.
Conflicts of Interest
The authors have no conflict of interest to declare.
This work was partially supported by “Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 11 Mandalay Road, Singapore 308232, Singapore, and Human Genetics, Genome Institute of Singapore, ASTAR, 60 Biopolis Street, Singapore 138672, Singapore.” We sincerely thank the patients and their families for their enthusiastic participation.
- C. Deveault, G. Billingsley, J. L. Duncan et al., “BBS genotype-phenotype assessment of a multiethnic patient cohort calls for a revision of the disease definition,” Human Mutation, vol. 32, no. 6, pp. 610–619, 2011.
- S. Katagiri, K. Hosono, T. Hayashi et al., “Novel biallelic splice-site BBS1 variants in Bardet–Biedle syndrome: a case report of the first Japanese patient,” Documenta Ophthalmologica., vol. 141, no. 1, pp. 77–88, 2020.
- O. M’Hamdi, I. Ouertani, and H. Chaabouni-Bouhamed, “Update on the genetics of Bardet-Biedl syndrome,” Molecular Syndromology, vol. 5, no. 2, pp. 51–56, 2014.
- S. J. Shin, M. Kim, H. Chae et al., “Identification of compound heterozygous mutations in the BBS7 gene in a Korean family with Bardet-Biedl syndrome,” Annals of Laboratory Medicine., vol. 35, no. 1, pp. 181–184, 2015.
- K. Jeziorny, K. Antosik, P. Jakiel, W. Młynarski, M. Borowiec, and A. Zmysłowska, “Next-generation sequencing in the diagnosis of patients with Bardet–Biedl syndrome—new variants and relationship with hyperglycemia and insulin resistance,” Genes, vol. 11, no. 11, p. 1283, 2020.
- S. J. Moore, J. S. Green, Y. Fan et al., “Clinical and genetic epidemiology of Bardet-Biedl syndrome in Newfoundland: a 22-year prospective, population-based, cohort study,” American Journal of Medical Genetics, vol. 132A, no. 4, pp. 352–360, 2005.
- T. Duelund Hjortshøj, K. Grønskov, K. Brøndum-Nielsen, and T. Rosenberg, “A novel founder BBS1 mutation explains a unique high prevalence of Bardet-Biedl syndrome in the Faroe Islands,” British Journal of Ophthalmology, vol. 93, no. 3, pp. 409–413, 2009.
- E. N. Suspitsin and E. N. Imyanitov, “Bardet-Biedl syndrome,” Molecular Syndromology., vol. 7, no. 2, pp. 62–71, 2016.
- M. A. Khan, S. Mohan, M. Zubair, and C. Windpassinger, “Homozygosity mapping identified a novel protein truncating mutation (p.Ser100Leufs24) of the BBS9 gene in a consanguineous Pakistani family with Bardet Biedl syndrome,” BMC Medical Genetics, vol. 17, no. 1, 2016.
- K. Weihbrecht, W. A. Goar, T. Pak et al., “Keeping an eye on Bardet-Biedl syndrome: a comprehensive review of the role of Bardet-Biedl syndrome genes in the eye,” Medical research archives, vol. 5, no. 9, pp. 14–16, 2017.
- E. Manara, S. Paolacci, F. D’Esposito et al., “Mutation profile of BBS genes in patients with Bardet-Biedl syndrome: an Italian study,” Italian Journal of Pediatrics, vol. 45, no. 1, pp. 72–78, 2019.
- R. L. Bennett, K. S. French, R. G. Resta, and D. L. Doyle, “Standardized human pedigree nomenclature: update and assessment of the recommendations of the National Society of Genetic Counselors,” Journal of Genetic Counseling., vol. 17, no. 5, pp. 424–433, 2008.
- F. Di Pietro, F. Ortenzi, M. Tilio, F. Concetti, and V. Napolioni, “Genomic DNA extraction from whole blood stored from 15- to 30-years at -20 °C by rapid phenol-chloroform protocol: a useful tool for genetic epidemiology studies,” Molecular and Cellular Probes, vol. 25, no. 1, pp. 44–48, 2011.
- A. González-Pérez and N. López-Bigas, “Improving the assessment of the outcome of nonsynonymous SNVs with a consensus deleteriousness score, Condel,” American Journal of Human Genetics, vol. 88, no. 4, pp. 440–449, 2011.
- J. Cheng, J. Baßler, P. Fischer et al., “Thermophile 90S Pre-ribosome Structures Reveal the Reverse Order of Co- transcriptional 18S rRNA Subdomain Integration,” Molecular Cell, vol. 75, no. 6, pp. 1256–1269.e7, 2019.
- A. Roy, A. Kucukural, and Y. Zhang, “I-TASSER: a unified platform for automated protein structure and function prediction,” Nature Protocols., vol. 5, no. 4, pp. 725–738, 2010.
- P. L. Beales, N. Elcioglu, A. S. Woolf, D. Parker, and F. A. Flinter, “New criteria for improved diagnosis of Bardet-Biedl syndrome: results of a population survey,” Journal of Medical Genetics., vol. 36, no. 6, pp. 437–446, 1999.
- T. D. Hjortshøj, K. Grønskov, A. R. Philp et al., “Bardet-Biedl syndrome in Denmark: report of 13 novel sequence variations in six genes,” Human Mutation., vol. 31, no. 4, pp. 429–436, 2010.
- S. M. Muns, L. A. Montalvo, J. G. Vargas Del Valle, M. Martinez, A. L. Oliver, and N. J. Izquierdo, “Clinical characteristics and ultra-widefield fundus image analysis of two siblings with Bardet-Biedl syndrome type 1 p.Met390Arg variant,” American Journal of Ophthalmology Case Reports, vol. 20, p. 100914, 2020.
- Z. Bahmanpour, Y. Daneshmandpour, S. Kazeminasab et al., “A novel splice site mutation in the SDCCAG8 gene in an Iranian family with Bardet–Biedl syndrome,” International Ophthalmology., vol. 123456789, 2020.
- E. Nikkhah, R. Safaralizadeh, J. Mohammadiasl, M. T. Birgani, M. A. H. Feizi, and N. Golchin, “Identification of a novel compound heterozygous mutation in BBS12 in an Iranian family with Bardet-Biedl syndrome using targeted next generation sequencing,” Cell Journal, vol. 20, no. 2, pp. 284–289, 2018.
- M. Muzammal, M. Zubair, S. Bierbaumer et al., “Exome sequence analysis in consanguineous Pakistani families inheriting Bardet-Biedle syndrome determined founder effect of mutation c.299delC (p.Ser100Leufs24) inBBS9gene,” Molecular Genetics and Genomic Medicine, vol. 7, no. 8, pp. e834–e836, 2019.
- M. Ajmal, M. I. Khan, K. Neveling et al., “Exome sequencing identifies a novel and a recurrent BBS1 mutation in Pakistani families with Bardet-Biedl syndrome,” Molecular vision, vol. 19, pp. 644–653, 2013.
- H. M. Harville, S. Held, A. Diaz-Font et al., “Identification of 11 novel mutations in eight BBS genes by high-resolution homozygosity mapping,” Journal of Medical Genetics., vol. 47, no. 4, pp. 262–267, 2010.
- S. J. Ansley, J. L. Badano, O. E. Blacque et al., “Basal body dysfunction is a likely cause of pleiotropic Bardet-Biedl syndrome,” Nature, vol. 425, no. 6958, pp. 628–633, 2003.
- M. Maria, I. J. C. Lamers, M. Schmidts et al., “Genetic and clinical characterization of Pakistani families with Bardet-Biedl syndrome extends the genetic and phenotypic spectrum,” Scientific Reports, vol. 6, no. 1, 2016.
- S. Ain-Ul-Batool, B. K. Sadia, A. Kaindl, and G. Ali, “A homozygous c.1131G>a missense mutation in BBS9 gene manifesting autosomal recessive Bardet-Biedl syndrome in consanguineous Kashmiri family,” Pakistan Journal of Zoology, vol. 51, no. 4, pp. 1575–1578, 2019.
- S. Khan and I. Ullah, “novel homozygous mutations in the genes ARL6 and BBS10 underlying Bardet-Biedl syndrome,” Gene, vol. 515, no. 1, pp. 84–88, 2013.
- Z. Agha, Z. Iqbal, M. Azam, L. H. Hoefsloot, H. van Bokhoven, and R. Qamar, “A novel homozygous 10 nucleotide deletion in BBS10 causes Bardet-Biedl syndrome in a Pakistani family,” Gene, vol. 519, no. 1, pp. 177–181, 2013.
- D. R. A. White, A. Ganesh, D. Nishimura et al., “Autozygosity mapping of Bardet-Biedl syndrome to 12q21.2 and confirmation of FLJ23560 as BBS10,” European Journal of Human Genetics., vol. 15, no. 2, pp. 173–178, 2007.
- B. Pawlik, A. Mir, H. Iqbal et al., “A novel familial BBS12 mutation associated with a mild phenotype: implications for clinical and molecular diagnostic strategies,” Molecular Syndromology., vol. 1, no. 1, pp. 27–34, 2010.
- M. Maria, I. J. C. Lamers, M. Schmidts et al., “Deciphering intrafamilial phenotypic variability by exome sequencing in a Bardet–Biedl family,” Molecular Genetics and Genomic Medicine., vol. 2, no. 2, pp. 124–133, 2014.
- R. Riise, S. Andreasson, M. K. Borgstrom et al., “Intrafamilial variation of the phenotype in Bardet-Biedl syndrome,” British Journal of Ophthalmology, vol. 81, no. 5, pp. 378–385, 1997.
- R. Novas, M. Cardenas-Rodriguez, F. Irigoín, and J. L. Badano, “Bardet-Biedl syndrome: is it only cilia dysfunction?” FEBS Letters., vol. 589, no. 22, pp. 3479–3491, 2015.
- Q. Zhang, D. Yu, S. Seo, E. M. Stone, and V. C. Sheffield, “Intrinsic protein-protein interaction-mediated and chaperonin-assisted sequential assembly of stable Bardet-Biedl syndrome protein complex, the BBSome,” Journal of Biological Chemistry., vol. 287, no. 24, pp. 20625–20635, 2012.
- G. Esposito, F. Testa, M. Zacchia et al., “Genetic characterization of Italian patients with Bardet-Biedl syndrome and correlation to ocular, renal and audio-vestibular phenotype: identification of eleven novel pathogenic sequence variants,” BMC Medical Genetics, vol. 18, no. 1, pp. 10–12, 2017.
- V. Niederlova, M. Modrak, O. Tsyklauri, M. Huranova, and O. Stepanek, “Meta-analysis of genotype-phenotype associations in Bardet-Biedl syndrome uncovers differences among causative genes,” Human Mutation, vol. 40, no. 11, pp. 2068–2087, 2019.
- Y. M. Bee, M. Chawla, and Y. Zhao, “Whole exome sequencing identifies a novel and a recurrent mutation in BBS2 gene in a family with Bardet-Biedl syndrome,” BioMed Research International, vol. 2015, 2015.
- L. Kordestani, Y. Amiri, W. Zulfiqar et al., “A novel mutation (Arg 413Ter) in the BBS2 gene in a consanguineous Pakistani family with Bardet–Biedl syndrome,” ARVO Annual Meeting Abstract, vol. 47, no. 13, 2006.
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