Spondylothoracic dysplasia with diaphragmatic defect: a case report with literature review

Sporadic Occurrence of Jarcho-Levin Syndrome in an Ivorian Newborn

We report on an isolated chest-wall asymmetry with imaging findings of multiple vertebral and related rib defects in an Ivorian male newborn. He was born of a healthy and young couple without parental lineage, neither family malformative history nor teratogen exposure. This clinical presentation advocates Jarcho-Levin syndrome, a rare sporadic or familial disorder inherited as autosomal dominant or recessive mode and manifested by extensive vertebral segmentation defects with distinctive rib structural and morphological anomalies. According to our belief, this disorder has not been previously traced in the sub-Saharan African area.

Defective somitogenesis and abnormal vertebral segmentation in man

In recent years molecular genetics has revolutionized the study of somitogenesis in developmental biology and advances that have taken place in animal models have been applied successfully to human disease. Abnormal segmentation in man is a relatively common birth defect and advances in understanding have come through the study of cases clustered in families using DNA linkage analysis and candidate gene approaches, the latter stemming directly from knowledge gained through the study of animal models. Only a minority of abnormal segmentation phenotypes appear to follow Mendelian inheritance but three genes--DLL3, MESP2 and LNFG--have now been identified for spondylocostal dysostosis (SCD), a spinal malformation characterized by extensive hemivertebrae, trunkal shortening and abnormally aligned ribs with points of fusion. In affected families autosomal recessive inheritance is followed. These genes are all important components of the Notch signaling pathway. Other genes within the pathway cause diverse phenotypes such as Alagille syndrome (AGS) and CADASIL, conditions that may have their origin in defective vasculogenesis. This review deals mainly with SCD, with some consideration of AGS. Significant future challenges lie in identifying causes of the many abnormal segmentation phenotypes in man but it is hoped that combined approaches in collaboration with developmental biologists will reap rewards.

Single gene disorders associated with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common birth defect with a high pre- and postnatal mortality. Although the majority of diaphragmatic hernias occur as isolated malformations, additional major and minor anomalies are common and are present in more than 40% of patients. There are compelling data for the importance of genetic factors in the etiology of CDH, but the pathogenesis and the causative genes for CDH in humans remain elusive. There are more than 70 syndromes in which diaphragmatic hernias have been described, and several of these syndromes are single gene disorders for which the gene is known. One method for identifying the causative genes in isolated CDH is to study syndromes with known genes in which CDH is a recognized feature, with the rationale that those genes have a role in diaphragm development. This review discusses the syndromes that are most commonly associated with CDH, with greater attention towards syndromes in which the causative genes have been identified, including Simpson-Golabi-Behmel syndrome, Denys-Drash syndrome, spondylocostal dysostosis, craniofrontonasal syndrome, Cornelia de Lange syndrome and Marfan syndrome.

Diaphragmatic hernia and preaxial polydactyly in spondylothoracic dysplasia

We report on two cases (male twins), and a female sib terminated at 20 weeks, whose autopsy revealed features of spondylothoracic dysplasia (STD) and also a diaphragmatic hernia and preaxial polydactyly. We present the findings and review STD and the closely related spondylocostal dysostosis. On the basis of the discussion we suggest that our cases are possibly the first report of preaxial polydactyly in spondylothoracic dysplasia and that STD and spondylocostal dysostosis may be allelic.

Aberrant Pax1 and Pax9 expression in Jarcho-Levin syndrome: report of two Caucasian siblings and literature review

We report two consecutive Caucasian male siblings of nonconsanguineous parents autopsied at 22 and 13 weeks gestational age both with prenatal diagnosis of Jarcho-Levin syndrome (JLS). Segmentation anomalies of the vertebrae and ribs encompass a spectrum of syndromes with or without associated anomalies of other developmental fields, and include spondylothoracic dysostosis (STD), JLS, Casamassima-Morton-Nance (CMN) syndrome, and spondylocostal dysostosis (SCD), among others. In both these new JLS cases the autopsies confirmed that there were severe developmental alterations in the thoracic and vertebral skeleton (including "crab-like" thorax), accompanied in the older fetus by renal defects. Because vertebral development is controlled by a limited number of master genes including Pax1 and Pax9, we analyzed protein expression from these genes in these two cases compared to age-matched controls. Immunochemical analysis showed a significant reduction in levels of Pax1 and Pax9 protein expression in chondrocytes of the vertebral column. Implications for the etiology and pathogenesis of JLS and related disorders are discussed.