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.

To investigate the genetic basis of recessively-inherited congenital, non syndromic, bilateral, total sclerocornea in two consanguineous pedigrees, one from the Punjab province of Pakistan and the other from the Tlaxcala province of Mexico.

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

Making oral contraceptives (OC) available over the counter (OTC) could reduce barriers to use. To inform WHO guidelines on self-care interventions, we conducted a systematic review of OTC availability of OCs.

The atonal homolog 7 (ATOH7) gene encodes a transcription factor involved in determining the fate of retinal progenitor cells and is particularly required for optic nerve and ganglion cell development. Using a combination of autozygosity mapping and next generation sequencing, we have identified homozygous mutations in this gene, p.E49V and p.P18RfsX69, in two consanguineous families diagnosed with multiple ocular developmental defects, including severe vitreoretinal dysplasia, optic nerve hypoplasia, persistent fetal vasculature, microphthalmia, congenital cataracts, microcornea, corneal opacity and nystagmus. Most of these clinical features overlap with defects in the Norrin/β-catenin signalling pathway that is characterized by dysgenesis of the retinal and hyaloid vasculature. Our findings document Mendelian mutations within ATOH7 and imply a role for this molecule in the development of structures at the front as well as the back of the eye. This work also provides further insights into the function of ATOH7, especially its importance in retinal vascular development and hyaloid regression.

A dearth of qualitative studies constrains in-depth understanding of health service providers' perspectives and experiences regarding the impact of COVID-19 on their mental health. This study explored the mental health impact and needs of of public sector healthcare workers during COVID-19 who working in secondary-level and tertiary-level healthcare settings of Pakistan.

Amelogenesis is the process of dental enamel formation, leading to the deposition of the hardest tissue in the human body. This process requires the intricate regulation of ion transport and controlled changes to the pH of the developing enamel matrix. The means by which the enamel organ regulates pH during amelogenesis is largely unknown. We identified rare homozygous variants in GPR68 in three families with amelogenesis imperfecta, a genetically and phenotypically heterogeneous group of inherited conditions associated with abnormal enamel formation. Each of these homozygous variants (a large in-frame deletion, a frameshift deletion, and a missense variant) were predicted to result in loss of function. GPR68 encodes a proton-sensing G-protein-coupled receptor with sensitivity in the pH range that occurs in the developing enamel matrix during amelogenesis. Immunohistochemistry of rat mandibles confirmed localization of GPR68 in the enamel organ at all stages of amelogenesis. Our data identify a role for GPR68 as a proton sensor that is required for proper enamel formation.

Research of the human brain metabolism in vivo has largely focused on total glucose use (via fluorodeoxyglucose positron emission tomography) and, until recently, did not examine the use of glucose outside oxidative phosphorylation, which is known as aerobic glycolysis (AG). AG supports important functions including biosynthesis and neuroprotection but decreases dramatically with aging. This multitracer positron emission tomography study evaluated the relationship between AG, total glucose use (CMRGlc), oxygen metabolism (CMRO2), tau, and amyloid deposition in 42 individuals, including those at preclinical and symptomatic stages of Alzheimer's disease. Our findings demonstrate that in individuals with amyloid burden, lower AG is associated with higher tau deposition. No such correlation was observed for CMRGlc or CMRO2. We suggest that aging-related loss of AG leading to decreased synaptic plasticity and neuroprotection may accelerate tauopathy in individuals with amyloid burden. Longitudinal AG and Alzheimer's disease pathology studies are needed to verify causality.

Primary congenital glaucoma (PCG) is an autosomal-recessive condition characterized by high intraocular pressure (IOP), usually within the first year of life, which potentially could lead to optic nerve damage, globe enlargement, and permanent loss of vision. To date, PCG has been linked to three loci: 2p21 (GLC3A), for which the responsible gene is CYP1B1, and 1p36 (GLC3B) and 14q24 (GLC3C), for which the genes remain to be identified. Here we report that null mutations in LTBP2 cause PCG in four consanguineous families from Pakistan and in patients of Gypsy ethnicity. LTBP2 maps to chromosome 14q24.3 but is around 1.3 Mb proximal to the documented GLC3C locus. Therefore, it remains to be determined whether LTBP2 is the GLC3C gene or whether a second adjacent gene is also implicated in PCG. LTBP2 is the largest member of the latent transforming growth factor (TGF)-beta binding protein family, which are extracellular matrix proteins with multidomain structure. It has homology to fibrillins and may have roles in cell adhesion and as a structural component of microfibrils. We confirmed localization of LTBP2 in the anterior segment of the eye, at the ciliary body, and particularly the ciliary process. These findings reveal that LTBP2 is essential for normal development of the anterior chamber of the eye, where it may have a structural role in maintaining ciliary muscle tone.

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.

Background: There are few evidence-based non-pharmacological interventions adapted for people with dementia (PwD) in lower- and middle-income countries (LMIC). Thus, there is value in culturally adapting existing interventions from other settings. One such intervention for PwD involves hearing rehabilitation, which may improve dementia-related outcomes. Objective: To culturally adapt and evaluate the feasibility and acceptability of a multi-faceted hearing support intervention to enhance quality of life in PwD for a LMIC setting, Pakistan. Design: This was a study in three phases: (1) training and capacity building to deliver the study, including Patient and Public Involvement (PPI); (2) cultural adaptation of the intervention; and (3) delivery of a single-group feasibility study with a pre-test post-test design. Setting: Home-based intervention, in two cities of Pakistan. Participants: Adults aged ≥ 60 with mild-moderate dementia and uncorrected or partially corrected hearing impairment, and their study partners (n = 14). Intervention: An adapted hearing support intervention (HSI) comprising a full assessment of hearing function, fitting of hearing aids, and home-based support from a "hearing support practitioner." Outcomes: Ratings of the feasibility of the study procedures, and acceptability/tolerability of the adapted intervention were ascertained through questionnaires, participant diaries, therapist logbooks and semi-structured interviews. A signal of effectiveness of the intervention was also explored using a battery of dementia-related outcome measures. Results: Following cultural adaptation and capacity building for study conduct and delivery, we successfully implemented all intervention components in most participants, which were well-received and enacted by participant dyads. Acceptability (i.e., understanding, motivation, sense of achievement) and tolerability (i.e., effort, fatigue) ratings and safety of the intervention were within a priori target ranges. Recruitment and retention targets required improvement, due to the COVID-19 pandemic outbreak, as well as the lack of a clear clinical diagnostic pathway for dementia in both sites. Areas for future modification were clearly identified, including: the assessment/delivery logistics circuit; procedures for arranging visits; communication among referring clinicians and the study team. Conclusion: This is the first study in a LMIC of sensory enhancement to improve dementia outcomes. Positive feasibility, acceptability and tolerability findings suggest that a full-scale effectiveness trial, with certain modifications is warranted.

Anterior segment dysgenesis describes a group of heterogeneous developmental disorders that affect the anterior chamber of the eye and are associated with an increased risk of glaucoma. Here, we report homozygous mutations in peroxidasin (PXDN) in two consanguineous Pakistani families with congenital cataract-microcornea with mild to moderate corneal opacity and in a consanguineous Cambodian family with developmental glaucoma and severe corneal opacification. These results highlight the diverse ocular phenotypes caused by PXDN mutations, which are likely due to differences in genetic background and environmental factors. Peroxidasin is an extracellular matrix-associated protein with peroxidase catalytic activity, and we confirmed localization of the protein to the cornea and lens epithelial layers. Our findings imply that peroxidasin is essential for normal development of the anterior chamber of the eye, where it may have a structural role in supporting cornea and lens architecture as well as an enzymatic role as an antioxidant enzyme in protecting the lens, trabecular meshwork, and cornea against oxidative damage.

Meckel-Gruber syndrome (MKS) is an autosomal recessive lethal condition that is a ciliopathy. MKS has marked phenotypic variability and genetic heterogeneity, with mutations in nine genes identified as causative to date.