Risk Factors for Development of Keratoconus: A Matched Pair Case-Control Study

BACKGROUND

Keratoconus, a progressive ectatic corneal disorder, is believed to be multifactorial in etiology with interaction between genetic and environmental factors. To date, risk factors for the development of the disease are extensively debated and need to be identified since they play a critical role in disease prevention and management. This study aimed to analyze associations between several hereditary and environmental predictors and the development of keratoconus.

PATIENTS AND METHODS

This was a retrospective matched pair case-control study. The study was conducted in Ibn-Alhaitham eye teaching hospital between March 2016 and April 2017. Patients with keratoconus (cases) and their age- and gender-matched controls were asked about childhood and early teenage eye rubbing, ocular trauma, obesity, contact lens wear, smoking and sunlight exposure, family history of keratoconus, parental consanguinity and information related to socio-economic status. Univariable and multivariable conditional logistic regression analyses were used to test the significance of associations.

RESULTS

A total of 166 individuals (83 cases and 83 controls; 60.2% female) were included. On univariable analysis, eye rubbing, family history of keratoconus and parental consanguinity were significant risk factors for keratoconus, whereas all other factors were non-significant. On multivariable analysis, eye rubbing (odds ratio: 4.93; P < 0.01), family history of keratoconus (odds ratio: 25.52; P < 0.01) and parental consanguinity (odds ratio: 2.89; P = 0.02), again, emerged as significant risk factors for disease development.

CONCLUSION

Family history of keratoconus, eye rubbing, and parental consanguinity were significant risk factors for keratoconus development. These results support the evidence for multifactorial etiology, the most important factor being hereditary predisposition.

Familial aggregation of multiple sclerosis: Results from the national registry of the disease in Saudi Arabia

Background

Multiple Sclerosis (MS) is a chronic CNS inflammatory disease commonly affecting young adults. Both genetics and environmental factors have been reported to have a role in pathophysiology of the disease.

Objective

This article aims to report familial nature and aspects of MS in Saudi Arabia.

Method

The study utilized data collected by the National Saudi MS Registry between 2015 and 2018; especially data relevant to the familial history of MS. SPSS 22 was used for all analysis and reporting. Statistical significance was set at p-value < 0.05.

Results

The registry included 20 hospitals and a total of 2516 patients from the different regions of Saudi Arabia with median age 32.00 (Range: 11-63) and 66.5% being female. About 12.8% of all registered patients reported a family history of MS (95%CI: 11.2-13.9). Reported parental consanguinity was significantly higher among patients with family history (FMS) (56.3%) compared to non-FMS patients (27.9%). 42.53% of FMS patients reported having siblings affected with MS (95%CI: 37.01-48.21), with more female siblings affected than males (63.4% vs 36.6% respectively).

Conclusion

Our Findings suggested that FMS was less prevalent than what was reported previously; however, parental consanguinity was significantly more prevalent among FMS patients than non-FMS. Our findings were in line with those reported in recent studies in the region, but lower than those reported by western countries indicating that increasing prevalence of MS in Saudi Arabia could be multifactorial and other environmental factors should be considered for understanding this recent rise in the prevalence of MS in Saudi Arabia.

Recurrence of First Afebrile Unprovoked Seizure and Parental Consanguinity: A Hospital-Based Study

PURPOSE

The aim of the current study was to determine the incidence, clinical characteristics, and risk factors associated with the recurrence of first unprovoked seizure in children.

METHODS

A retrospective, observational study was conducted at King Abdullah University Hospital in Jordan. Children aged from 1 month to 16 years old who attended the hospital between January 2013 to December 2017 were evaluated on the basis of medical records, from the first visit and for a 1-year follow-up period.

RESULTS

During the study period, a total of 290 cases with first unprovoked seizure were included. The incidence of first unprovoked seizure was 441 cases per 100 000 patient visits to the pediatric clinic. More than half of the cases developed a second attack (55.3%). Children with parental consanguinity were almost 3 times more likely to develop a second attack of seizure compared to those without parental consanguinity (odds ratio [OR] = 2.785, 95% confidence interval [CI] = 1.216-6.378, P = .015) and patients who had a history of focal type of seizure were almost twice as likely to develop seizure recurrence (OR = 1.798, 95% CI = 1.013-3.193, P = .045).

CONCLUSIONS

The current results showed a high incidence of first unprovoked seizure among children in Jordan. Parental consanguinity and focal seizure were associated with the increased risk of recurrent attack. This finding highlights the need for public education regarding the outcomes of parental consanguinity to improve the patient's quality of life.

Effect of inbreeding on intellectual disability revisited by trio sequencing

In outbred Western populations, most individuals with intellectual disability (ID) are sporadic cases, dominant de novo mutations (DNM) are frequent, and autosomal recessive ID (ARID) is very rare. Because of the high rate of parental consanguinity, which raises the risk for ARID and other recessive disorders, the prevalence of ID is significantly higher in near- and middle-east countries. Indeed, homozygosity mapping and sequencing in consanguineous families have already identified a plethora of ARID genes, but because of the design of these studies, DNMs could not be systematically assessed, and the proportion of cases that are potentially preventable by avoiding consanguineous marriages or through carrier testing is hitherto unknown. This prompted us to perform whole-exome sequencing in 100 sporadic ID patients from Iran and their healthy consanguineous parents. In 61 patients, we identified apparently causative changes in known ID genes. Of these, 44 were homozygous recessive and 17 dominant DNMs. Assuming that the DNM rate is stable, these results suggest that parental consanguinity raises the ID risk about 3.6-fold, and about 4.1 to 4.25-fold for children of first-cousin unions. These results do not rhyme with recent opinions that consanguinity-related health risks are generally small and have been "overstated" in the past.

Genealogical and molecular analysis of a family-based cohort of congenital heart disease patients from the São Miguel Island (Azores, Portugal)

BACKGROUND

Congenital heart disease (CHD) is one common birth malformation, accounting for ∼30% of total congenital abnormalities.

AIM

Considering the unknown role of consanguinity in causing CHD, this study hypothesised that consanguineous unions and/or familial aggregation may be frequent in the Azorean Island of São Miguel (Portugal). To that end, a retrospective observational study was performed based on genealogical and molecular analyses.

SUBJECTS AND METHODS

The study enrolled 112 CHD patients from São Miguel Island, which allowed the assessment of type of family (simplex or multiplex), parental consanguinity and grandparental endogamy. Based on 15 STR markers, inbreeding coefficients (F_IS) in the CHD cohort and healthy control group (n = 114) were estimated.

RESULTS

Multiplex families were 37.6% (n = 41/109), a rate considerably higher than previously described in the literature (< 15%). Moreover, 9.2% (n = 10/109) of the CHD families were consanguineous, mostly derived from third cousin unions, and 20.2% (n = 22/109) presented full grandparental endogamy. Higher F_IS values were found in patients with parental consanguinity (0.0371) and patent ductus arteriosus (0.0277).

CONCLUSION

This study analysed several genealogical and genetic features related with CHD, revealing the presence of parental consanguinity and extensive familial aggregation in the CHD patients from São Miguel Island.