First case of Moebius-Poland syndrome in child prenatally exposed to misoprostol

Physiopathologic Bases of Moebius Syndrome: Combining Genetic, Vascular, and Teratogenic Theories

Moebius syndrome (MBS) is a congenital cranial dysinnervation disorder (CCDD) characterized by a bilateral palsy of abducens and facial cranial nerves, which may coexist with other cranial nerves palsies, mostly those found in the dorsal pons and medulla oblongata. MBS is considered a "rare" disease, occurring in only 1:50,000 to 1:500,000 live births, with no gender predominance. Three independent theories have been described to define its etiology: the vascular theory, which talks about a transient blood flow disruption; the genetic theory, which takes place due to mutations related to the facial motor nucleus neurodevelopment; and last, the teratogenic theory, associated with the consumption of agents such as misoprostol during the first trimester of pregnancy. Since the literature has suggested the existence of these theories independently, this review proposes establishing a theory by matching the MBS molecular bases. This review aims to associate the three etiopathogenic theories at a molecular level, thus submitting a combined postulation. MBS is most likely an underdiagnosed disease due to its low prevalence and challenging diagnosis. Researching other elements that may play a key role in the pathogenesis is essential. It is common to assume the difficulty that patients with MBS have in leading an everyday social life. Research by means of PubMed and Google Scholar databases was carried out, same in which 94 articles were collected by using keywords with the likes of "Moebius syndrome," "PLXND1 mutations," "REV3L mutations," "vascular disruption AND teratogens," and "congenital facial nerve palsy." No exclusion criteria were applied.

Poland-Möbius syndrome: a case report implicating a novel mutation of the PLXND1 gene and literature review

BACKGROUND

Möbius (Moebius) and Poland's syndromes are two rare congenital syndromes characterized by non-progressive bilateral (and often asymmetric) dysfunction of the 6^th and 7^th cranial nerves and hypoplasia of the pectoral muscles associated with chest wall and upper limb anomalies respectively. Manifest simultaneously as Poland-Möbius (Poland-Moebius) syndrome, debate continues as to whether this is a distinct nosological entity or represents phenotypic variation as part of a spectrum of disorders of rhomboencephalic development. Etiological hypotheses implicate both genetic and environmental factors. The PLXND1 gene codes for a protein expressed in the fetal central nervous system and vascular endothelium and is thus involved in embryonic neurogenesis and vasculogenesis. It is located at chromosome region 3q21-q22, a locus of interest for Möbius syndrome.

CASE PRESENTATION

We present the first report of a patient with Poland-Möbius syndrome and a mutation in the PLXND1 gene. A child with Poland-Möbius syndrome and a maternally inherited missense variant (NM_015103.2:ex14:c.2890G > Ap.V964M) in the PLXND1 gene is described. In order to contextualize these findings, the literature was examined to identify other confirmed cases of Poland-Möbius syndrome for which genetic data were available. Fourteen additional cases of Poland-Möbius syndrome with genetic studies are described in the literature. None implicated the PLXND1 gene which has previously been implicated in isolated Möbius syndrome.

CONCLUSIONS

This report provides further evidence in support of a role for PLXND1 mutations in Möbius syndrome and reasserts the nosological link between Möbius and Poland's syndromes.

LEVEL OF EVIDENCE

Level V, Descriptive Study.

Poland Sequence: Retrospective Analysis of 66 Cases

INTRODUCTION AND OBJECTIVES

The literature reports many variations of Poland syndrome, which is a congenital disorder and a rare condition. The associated features are extremely variable, including alterations in the ipsilateral thorax and upper extremity and other malformations. This is used to designate the condition as Poland sequence (PS) because a sequence is a primary defect with a secondary cascade of structural changes. It is generally accepted that it is characterized as pathognomonic by absence/aplasia of the sternocostal aspect of the pectoralis major muscle of one side. Because it is considered a rare disease, and the incidence is low, we aimed to determine the features in all patients diagnosed at our institution to analyze the patterns and outcomes. We also revised the diagnosis according to the new classification proposed by Romanini et al to facilitate future treatments as well as to propose an improvement in the assessment and initial behavior when PS is suspected.

METHODS

We performed a retrospective study using our database from 1988. We identified 66 patients with a clinical diagnosis of PS in the Pediatric Plastic Surgery Unit of Hospital Sant Joan de Deu, Barcelona. We analyzed the medical charts, records, photographs, and imaging information to gather all the epidemiological information and clinical history, as well as the treatments received to analyze our experience with these patients. We used the TBN classification of Romanini et al, adding an S if there was upper extremity involvement (TBNS).We also conducted a systematic review consulting the following databases: PubMed, Cochrane Plus, Scopus, Web of Science, and Europe PMC.

RESULTS

Among the 66 patients, 27 were men, and 39 were women. The right side was affected in 51 patients (77.3%) (19 men and 32 women). In a total of 37 patients (56.1%; 16 men and 21 women), there was no upper extremity involvement. We found 40 cases with other associations, with scoliosis being the most common. Before 2007, the team performed surgery in 1 male patient and 4 female patients; after 2007, the actual team has performed reconstruction in 8 male patients and 16 female patients. In the female patients, the average volume of breast implants was 252.5 cc, and the average volume for fat grafting was 103.5 cc on the side affected with PS. There is a wide range of chest-breast clinical involvement, which was why we decided to readdress all the imaging and clinical history to classify the patients using a new classification system to learn how to optimally treat these cases in the future. In female patients, we used Romanini's TBN classification and added an S for upper extremity involvement; the T1B1N1S0 was the most frequently observed classification. Owing to the sample size and the disparity in sex distribution, we also reassessed publications in PubMed, Cochrane Plus, Scopus, Web of Science, and Europe PMC with more than 5 cases; we found that there were a total of 1600 patients with PS in the literature and that the distribution was almost 50% for men and women, including the patients in our study (611 women, 561 men).

CONCLUSIONS

We propose to include the presence of upper extremity involvement in Romanini's TBN classification (TBNS) for optimal management of these patients and use a standard number and profile for image documentation presurgery and postsurgery. We found that in the literature the ratio of men and women with PS was not 2 to 3:1, but 1:1. The most frequent phenotype of PS was T1B1N1S0 (hypoplasia or aplasia of the pectoralis muscles and soft tissue/breast hypoplasia/nipple-areolar complex with dislocation of <2 cm / absence of upper extremity involvement). There was no relationship between the side involved and patients' sex for the severity of the deformity and between the severity of the thoracic involvement and ipsilateral upper extremity association. In the literature, there are several plastic reconstruction methods available ranging from standard implants to microsurgery techniques. The selected procedure depends on the phenotype, patients' needs and expectations, availability of surgery in the hospital, and surgeons' criteria; thus, surgery has to be personalized while providing a match related to the risk/benefit, taking into account the degree of functional impairment. Since the author started her practice in the hospital in 2007, the timing for procedures has been proposed at the end of adolescence with 2 consecutive appointments without changes in the breast-thorax measures. The procedure performed has included implant use with lipofilling, yielding no major complications and a high rate of satisfaction during a maximum of 10 years of follow-up.

Examining the genetics of congenital facial paralysis--a closer look at Moebius syndrome

OBJECTIVES

The molecular underpinnings of Moebius syndrome (MBS) are diverse. This article provides a comprehensive summation of the genetic and etiologic literature underlying this disorder. Elucidating the genetic causes of the disorder can aid in earlier detection and treatment planning.

DESIGN

Articles from 1880-2013 were selected and reviewed by six researchers to understand all of the molecular theories and chronicity of advancements in the literature.

RESULTS

Mutations in the MBS1, MBS2, and MBS3 gene loci all have contributed to the development of MBS through various pathways. HOX family genes coding for homeobox domains, also, have been implicated in the abnormal development of the human brain. These are among the numerous genes that have been linked to the development of MBS.

CONCLUSION

Our study codified nascent findings of the molecular determinants of MBS. These findings add to a growing database of MBS-associated mutations and can be used to diagnose MBS and clarify pathogenesis.

A unique variant of Poland-Mobius syndrome with dextrocardia and a 3q23 gain

The combined Poland and Mobius syndrome occurs rarely and with a wide range of features. There is no consensus on the etiology of this syndrome; familial, sporadic cases and likely environmental insult cases have been reported. This sporadic case represents a unique variant in the spectrum of this syndrome.

Familial Poland anomaly revisited

Poland anomaly (PA) is a pectoral muscle hypoplasia/aplasia variably associated with ipsilateral thoracic (TA) and/or upper limb anomalies (ULA). PA is usually sporadic and sometimes familial, making recurrence risk an issue in genetic counseling. Multidisciplinary evaluation of 240 PA patients was carried out, including physical examination of patients and their parents in 190 PA (subjects of the study). Familial conditions were classified into three groups. Group1: true familial PA (F-PA): pectoral muscle defects with familial recurrence: 8(4.2%). Group2: familial Poland-like anomaly families (F-PLA): PA index case and ≥1 relative(s) showing normal pectoral muscles but ULA and/or TA common in PA: 16(8.4%). Group3: sporadic PA (S-PA): 166(87.4%). F-PA indicated a stronger male (87.5%) and left side (62.5%) prevalence, but fewer ULA (37.5%) compared to the other two groups. Maternal transmission (6/8) was more common in F-PA. Statistical significance was not reached due to the small number of F-PA and F-PLA. Karyotyping and array-comparative genomic hybridization were performed in 13 families. Three maternally inherited copy number variants were identified in three patients: 1p31.1 deletion, Xp11.22 duplication, and 16q23.1 duplication. Interestingly, the proband's mother carrying the 16q23.1 duplication displayed moderate breast and areola asymmetry, but normal pectoral muscles on ultrasound. Though there is no recent review discussing recurrence of PA, we reviewed 31 published PA families. On the basis of our study and previous reports, familial PA is not uncommon. Nonetheless, no information can be derived either regarding a molecular basis or clinical tools with which to identify cases with recurrence risk.