Rarity of Laurence Moon Bardet Biedl Syndrome and its Poor Management in the Pakistani Population

Megaloblastic Anemia in Bardet-Biedl Syndrome: A Rare Case Report

Background

Bardet-Biedl syndrome (BBS) also known as Laurence-Moon-Bardet-Biedl syndrome one of the rarely reported genetic disorder characterized by an intellectual disability, limb, kidney abnormalities, obesity, and Rod-cone dystrophy. Other associated condition includes diabetes mellitus, hypertension, hypogonadism, facial dysmorphism, and congenital heart defects. This case highlights megaloblastic anemia associated with BBS.

Case presentation

A 16-year-old female patient who had a moon face, truncal obesity, polydactyly, low IQ, and visual impairment presented with the complaint of shortness of breath and easy fatiguability. She had bilateral retinal pigmentosa in her eyes and her laboratory evaluation and bone marrow biopsy revealed megaloblastic anemia secondary to vitamin B12 deficiency. She received injectable vitamin B12, folate, and red cell contrate transfusion. Her symptoms improved and she was discharged with oral medication.

Conclusion

Megaloblastic anemia in BBS is rarely reported, further research is needed to find the exact cause that is necessary for proper management and better outcome.

Bardet-Biedl Syndrome: Current Perspectives and Clinical Outlook

The Bardet Biedl syndrome (BBS) is a rare inherited disorder considered a model of non-motile ciliopathy. It is in fact caused by mutations of genes encoding for proteins mainly localized to the base of the cilium. Clinical features of BBS patients are widely shared with patients suffering from other ciliopathies, especially autosomal recessive syndromic disorders; moreover, mutations in cilia-related genes can cause different clinical ciliopathy entities. Besides the best-known clinical features, as retinal degeneration, learning disabilities, polydactyly, obesity and renal defects, several additional clinical signs have been reported in BBS, expanding our understanding of the complexity of its clinical spectrum. The present review aims to describe the current knowledge of BBS i) pathophysiology, ii) clinical manifestations, highlighting both the most common and the less described features, iii) current and future perspective for treatment.

Novel biallelic variant in BBS9 causative of Bardet-Biedl syndrome: expanding the spectrum of disease-causing genetic alterations

Background

Bardet–Biedl syndrome (BBS) is a rare autosomal recessive ciliopathy disorder. Many BBS disease-causing genetic variants have been identified due to the advancement of molecular diagnostic tools. We report on a novel pathogenic variant in a consanguineous Pakistani family with an affected child.

Case presentation

Clinical exome sequencing was used to search for BBS causing variants in the affected individual and identified a novel homozygous splice-site variant in the BBS9 gene (c.702 + 1del). Sanger sequencing was performed for variant validation and segregation studies. Expression analysis using mRNA levels to assess the functional impact of the novel variant demonstrated skipping of exon 7 in the affected alleles, suggesting a truncating effect. Three-dimensional structural modelling was used to predict pathogenicity of the variant residue and the alteration leads to a partial deletion of the PHTB1_N domain and a total deletion of the PHTB1_C domain.

Conclusion

The study of this case expands the spectrum of biallelic variants in the BBS9 gene associated with BBS and increased the knowledge on the molecular consequences of splicing variation c.702 + 1del.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-00943-w.

Laurence-Moon-Bardet-Biedl Syndrome: A Rare Case With a Literature Review

Laurence-Moon-Bardet-Biedl syndrome (LMBBS), a rare autosomal recessive genetic disorder, results from consanguineous marriage. It is a congenital ciliopathy manifesting with primary and secondary characteristics. Primary clinical features include rod and cone dystrophy, polydactyly, central obesity, genital abnormalities, and mental retardation, often presenting as poor schooling skills. Secondary clinical features include developmental delay, speech deficit, brachydactyly/syndactyly, dental defects, ataxia, olfactory deficit, diabetes mellitus (DM), and congenital heart disease. Herein, we report a case of a 15-year-old male with clinical manifestations of LMBBS, namely learning disabilities, night blindness, hypogonadism, polydactyly, polysyndactyly, and obesity. Physicians must be familiar with this syndrome, for which an early diagnosis, multidisciplinary approach, and regular follow-ups can profoundly diminish morbidity and mortality in LMBBS patients.