OEIS complex: Prevalence, clinical, and epidemiologic findings in a multicenter Mexican birth defects surveillance program

Bayesian polygenic risk estimation approach to nuclear families with discordant sib-pairs for myelomeningocele

Myelomeningocele (MMC) is the most severe and disabling form of spina bifida with chronic health multisystem complications and social and economic family and health systems burden. In the present study, we aimed to investigate the genetic risk estimate for MMC in a cohort of 203 Mexican nuclear families with discordant siblings for the defect. Utilizing a custom Illumina array, we analyzed 656 single nucleotide polymorphisms (SNPs) of 395 candidate genes to identify a polygenic risk profile for MMC. Through a family-based analysis employing the transmission disequilibrium test (TDT) and Bayesian analysis, we assessed risk alleles transmission and calculated conditional probabilities estimating a polygenic risk for MMC. Our findings reveal significant associations of six genes related to neural tube closure (PSMB4, ATIC, DKK2, PSEN2, C2CD3, and PLCB2), showing differences in risk allele transmission between affected and unaffected siblings. Bayesian analysis identified changes in the risk profile after initiating folic acid fortification in Mexico, showing an evident decline in the conditional risk from 1/156 to 1/304 respectively. Despite the decline, this represents a 5.84-fold increase in risk before fortification and a 2.99-fold increase post-fortification compared to the baseline risk level (1/910). Our study highlights the advantage of incorporating a Bayesian analytical methodology in families with discordant sib-pairs, offering insights into the polygenic risk estimate for MMC and, most probably, for other congenital malformations.

Cloacal Exstrophy Closure Without Osteotomy and Immobilization: A Recipe for Failure

BACKGROUND

Cloacal exstrophy (CE) remains one of the most severe birth defects compatible with life with a constellation of anomalies involving the bladder, genitalia, hindgut, and spinal cord. Pelvic osteotomy and immobilization have been utilized to facilitate bladder closure, yet their role as adjuncts remains a topic of debate. The authors sought to evaluate the outcomes of CE closure without the use of osteotomy or lower extremity (LE)/pelvic immobilization.

METHODS

An institutional database of 173 CE patients was reviewed for patients closed without osteotomy and/or limb immobilization. Patient records were reviewed for continence procedures, reclosure operations, and continence outcomes.

RESULTS

A total of 59 closure surgeries that met inclusion criteria were identified in 56 unique patients. Thirty-seven closure procedures developed eventual failure (63%) with secondary closure events also resulting in failure. Most closures did not use an osteotomy, 93.2%. LE immobilization-only was used in most closures (43/59), of which only 37% were successful. Failures were attributed to dehiscence (14/37), bladder prolapse (19/37), or both dehiscence and prolapse (4/37). The median age at closure was 3 days old (1-18.5 IQR) with the majority of closure events (47) closure events taking place in the newborn period. Median diastasis prior to primary closure was 6 cm (4.8-8 cm IQR). The median number of closure attempts needed to close the bladder was 2 (1-2 IQR). Of the 56 patients, 31 have >3 h of daytime continence, with the entirety of these patients catheterizing a stoma or below.

CONCLUSION

These results highlight the critical role of osteotomy and lower limb immobilization in successful closure of the bladder and abdominal wall in CE.

TYPE OF STUDY

Treatment Study.

LEVEL OF EVIDENCE

Level III.

Moderate altitude as a risk factor for isolated congenital malformations. Results from a case-control multicenter-multiregional study

BACKGROUND

Living in high-altitude regions has been associated with a higher prevalence of some birth defects. Moderate altitudes (1500-2500 m) have been associated with some congenital heart diseases and low birth weight. However, no studies have been conducted for other isolated congenital malformations.

OBJECTIVES

To estimate the prevalence at birth of isolated congenital malformations in low and moderate altitudes and to determine if moderate altitudes are a risk factor, such as high altitudes, for isolated congenital malformations adjusted for other factors.

METHODS

The study consisted of a case-control multicenter-multiregional study of 13 isolated congenital malformations. Cases included live births with isolated congenital malformations and controls at low (10-1433 m) and moderate altitudes (1511-2426 m) from a Mexican registry from January 1978 to December 2019. Prevalence per 10,000 (95% CI) per altitude group was estimated. We performed unadjusted and adjusted logistic regression models (adjusted for maternal age, parity, malformed relatives, socioeconomic level, and maternal diabetes) for each isolated congenital malformation.

RESULTS

Hydrocephaly and microtia had a higher at-birth prevalence, and spina bifida, preauricular tag, and gastroschisis showed a lower at-birth prevalence in moderate altitudes. Moderate altitudes were a risk factor for hydrocephaly (aOR 1.39), microtia (aOR 1.60), cleft-lip-palate (aOR 1.27), and polydactyly (aOR 1.32) and a protective effect for spina bifida (aOR 0.87) compared with low altitudes.

CONCLUSIONS

Our findings provide evidence that moderate altitudes as higher altitudes are an associated risk or protective factor to some isolated congenital malformations, suggesting a possible gradient effect.

Surveillance of multiple congenital anomalies; searching for new associations

Many human teratogens are associated with a spectrum of congenital anomalies rather than a single defect, and therefore the identification of congenital anomalies occurring together more frequently than expected may improve the detection of teratogens. Thirty-two EUROCAT congenital anomaly registries covering 6,599,765 births provided 123,566 cases with one or more major congenital anomalies (excluding chromosomal and genetic syndromes) for the birth years 2008-2016. The EUROCAT multiple congenital anomaly algorithm identified 8804 cases with two or more major congenital anomalies in different organ systems, that were not recognized as part of a syndrome or sequence. For each pair of anomalies, the odds of a case having both anomalies relative to having only one anomaly was calculated and the p value was estimated using a two-sided Fisher's exact test. The Benjamini-Hochberg procedure adjusted p values to control the false discovery rate and pairs of anomalies with adjusted p values < 0.05 were identified. A total of 1386 combinations of two anomalies were analyzed. Out of the 31 statistically significant positive associations identified, 20 were found to be known associations or sequences already described in the literature and 11 were considered "potential new associations" by the EUROCAT Coding and Classification Committee. After a review of the literature and a detailed examination of the individual cases with the anomaly pairs, six pairs remained classified as new associations. In summary, systematically searching for congenital anomalies occurring together more frequently than expected using the EUROCAT database is worthwhile and has identified six new associations that merit further investigation.

Long-Term Management of Problems in Cloacal Exstrophy: A Single-Institution Review

INTRODUCTION

Cloacal exstrophy (CE) is the most severe malformation of the exstrophy-epispadias complex. This study aims to discuss long-term sequela in a single major institution with a high volume of CE patients.

MATERIALS AND METHODS

A prospectively maintained database of 1490 patients on the exstrophy epispadias spectrum (145 cloacal exstrophy) from 1974 to 2023. The patient database was reviewed for CE patients >10 years of age for genitourinary, gastrointestinal, orthopedic, and psychosocial outcomes.

RESULTS

A total of 63 patients (43.4%) with ≥10 years of follow up were included for analysis. Thirty-nine (61.9%) patients were 18 years or older. Twenty-two (34.9%) patients were female and 39 (61.9%) male, 14 of whom were gender converted at birth. Two female patients conceived naturally and delivered via cesarean section. No male born CE patients had biological children. Catheterizable channels were common (45/63, 71.4%) and most (88.9%) were continent. Gastrointestinal diversion was managed mostly by colostomy (37/63, 58.7%). Three out of five (60.0%) patients who underwent PSARP were continent of stool. Twenty-two (34.9%) patients were wheelchair-bound. Psychosocial diagnoses included 52.4% (33/63) patients with anxiety/depression and 27.0% with chronic pain. Out of 56 patients evaluated by physical therapy, 75% were independent in ADL performance. Of patients older than 18, 79.5% (31/39) had attended college and 82.1% (32/39) were gainfully employed.

CONCLUSION

Advances in critical care, nutrition, gastrointestinal, orthopedic, and urologic management have resulted in survival rates approaching 100% among patients with CE. While these children face long-term sequela spanning various organ systems, many lead independent and fully-functional lives.

TYPE OF STUDY

Prognosis Study.

LEVEL OF EVIDENCE

Level IV.

NAD+ deficiency in human congenital malformations and miscarriage: A new model of pleiotropy

Pleiotropy is defined as the phenomenon of a single gene locus influencing two or more distinct phenotypic traits. However, nicotinamide adenine dinucleotide (NAD+) deficiency through diet alone can cause multiple or single malformations in mice. Additionally, humans with decreased NAD+ production due to changes in pathway genes display similar malformations. Here, I hypothesize NAD+ deficiency as a pleiotropic mechanism for multiple malformation conditions, including limb-body wall complex (LBWC), pentalogy of Cantrell (POC), omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex, vertebral-anal-cardiac-tracheoesophageal fistula-renal-limb (VACTERL) association (hereafter VACTERL), oculoauriculovertebral spectrum (OAVS), Mullerian duct aplasia-renal anomalies-cervicothoracic somite dysplasia (MURCS), sirenomelia, and urorectal septum malformation (URSM) sequence, along with miscarriages and other forms of congenital malformation. The term Congenital NAD Deficiency Disorder (CNDD) could be considered for patients with these malformations; however, it is important to emphasize there have been no confirmatory experimental studies in humans to prove this hypothesis. In addition, these multiple malformation conditions should not be considered individual entities for the following reasons: First, there is no uniform consensus of clinical diagnostic criteria and all of them fail to capture cases with partial expression of the phenotype. Second, reports of individuals consistently show overlapping features with other reported conditions in this group. Finally, what is currently defined as VACTERL is what I would refer to as a default label when more striking features such as body wall defects, caudal dysgenesis, or cloacal exstrophy are not present.

Recurrent constellations of embryonic malformations re-conceptualized as an overlapping group of disorders with shared pathogenesis

Several recurrent malformation associations affecting the development of the embryo have been described in which a genetic etiology has not been found, including LBWC, MURCS, OAVS, OEIS, POC, VACTERL, referred to here as "recurrent constellations of embryonic malformations" (RCEM). All are characterized by an excess of reported monozygotic discordant twins and lack of familial recurrence. We performed a comprehensive review of published twin data across all six phenotypes to allow a more robust assessment of the association with twinning and potential embryologic timing of a disruptive event. We recorded the type of twinning, any overlapping features of another RCEM, maternal characteristics, and the use of ART. Statistically significant associations included an excess of monozygotic twins and 80% discordance rate for the phenotype across all twins. There was an 18.5% rate of ART and no consistently reported maternal adverse events during pregnancy. We found 24 instances of co-occurrence of two RCEM, suggesting a shared pathogenesis across all RCEM phenotypes. We hypothesize the following timing for RCEM phenotypes from the earliest perturbation in development to the latest: LBWC, POC, OEIS, VACTERL, OAVS, then MURCS. The RCEM group of conditions should be considered a spectrum that could be studied as a group.