Spondylocostal dysostosis is a rare, heritable axial skeleton

Axial skeleton

The axial skeleton consists of the 80 bones along the central axis of the human body. It is composed of six parts; the human skull, the ossicles of the middle ear, the hyoid bone of the throat, the rib cage, sternum and the vertebral column...

 growth disorder. It is characterized by widespread and sometimes severe malformations of the vertebral column

Vertebral column

In human anatomy, the vertebral column is a column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx. It is situated in the dorsal aspect of the torso, separated by intervertebral discs...

 and ribs, shortened thorax

Thorax

The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...

, and moderate to severe scoliosis

Scoliosis

Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C" than a straight line...

 and kyphosis

Kyphosis

Kyphosis , also called roundback or Kelso's hunchback, is a condition of over-curvature of the thoracic vertebrae...

. Individuals with Jarcho-Levin typically appear to have a short trunk and neck, with arms appearing relatively long in comparison, and a slightly protuberant abdomen

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

. Severely affected individuals may have life-threatening pulmonary complications due to deformities of the thorax. The syndrome was first described by Saul Jarcho and Paul M. Levin at Johns Hopkins University

Johns Hopkins University

The Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...

 in 1938.

Genetics

Types include:

Type	OMIM	Gene	Locus
SCDO1		DLL3 DLL3 Delta-like 3 , also known as DLL3, is a protein which in humans is encoded by the DLL3 gene. Two transcript variants encoding distinct isoforms have been identified for this gene.- Function :...	19q13
SCDO2		MESP2 MESP2 Mesoderm posterior protein 2 , also known as class C basic helix-loop-helix protein 6 , is a protein that in humans is encoded by the MESP2 gene.- Function :...	15q26.1
SCDO3		LFNG LFNG LFNG O-fucosylpeptide 3-beta-N-acetylglucosaminyltransferase, also known as LFNG and Lunatic Fringe, is a human gene.-External links:* -Further reading:...	7p22
SCDO4		GDF6 GDF6 Growth differentiation factor 6 is a protein that in humans is encoded by the GDF6 gene.belonging to the transforming growth factor beta superfamily that may regulate patterning of the ectoderm by interacting with bone morphogenetic proteins, and control eye development....	8q22.1

Terminology

"Type 1" is also known as "Jarcho-Levin syndrome'".

While clinicians almost unanimously refer to the syndrome as "Jarcho-Levin", reports have variously labelled or referred to the condition as all of the following: Hereditary malformations of the vertebral bodies, hereditary multiple hemivertebrae, syndrome of bizarre vertebral anomalies, spondylocostal dysplasia, spondylothoracic dysplasia, costovertebral anomalies, costovertebral dysplasia, spondylothoracic dysplasia, occipito-facial-cervico-thoracic-abdomino-digital dysplasia (deemed "ridiculously long" and "unwarranted" by OMIM)http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=277300, and spondylocostal dysostosis.

A closely related condition termed "Costovertebral segmentation defect with mesomelia and peculiar facies", or Covesdem syndrome, was first described in 1978 in India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

.

Prognosis

Babies born with Jarcho-Levin may be very healthy and grow up to lead normal lives. However, many individuals with Jarcho-Levin suffer from problems of respiratory insufficiency secondary to volume-restricted thoraces. These individuals will often develop pulmonary complications and die in infancy or early childhood. The disparity in outcomes of those with the syndrome is related to the fact that Jarcho-Levin actually encompasses two or more distinct syndromes, each with its own range of prognoses. The syndromes currently recognized as subtypes of Jarcho-Levin are termed spondylothoracic dysplasia and spondylocostal dysostosis.

Subtypes and Characteristics

In 1968, Dr. David Rimoin and colleagues in Baltimore

Baltimore

Baltimore is the largest independent city in the United States and the largest city and cultural center of the US state of Maryland. The city is located in central Maryland along the tidal portion of the Patapsco River, an arm of the Chesapeake Bay. Baltimore is sometimes referred to as Baltimore...

 first distinguished between the two major presentations of Jarcho-Levin. Both conditions were characterized as failures of proper vertebral segmentation. However, the condition within the family described in their article appeared to be inherited in an autosomal dominant fashion and had a less severe course than that reported by other investigators. They specified their condition as spondylocostal dysplasia, which has since become known as spondylocostal dysostosis. The subtype of Jarcho-Levin with which they contrasted their reported cases to is now known as spondylothoracic dysplasia.

Spondylothoracic dysplasia

Spondylothoracic dysplasia, or STD, has been repeatedly described as an autosomal recessively inherited condition that results in a characteristic fan-like configuration of the ribs with minimal intrinsic rib anomalies. Infants born with this condition typically died early in life due to recurrent respiratory infections and pneumonia due to their restricted thorax. Recently, a report has documented that actual mortality associated with STD is only about 50%, with many survivors leading healthy, independent lives.

Spondylocostal dysostosis

In contrast to STD, the subtype spondylocostal dysostosis, or SCD features intrinsic rib anomalies, in addition to vertebral anomalies. Intrinsic rib anomalies include defects such as birfurcation, broadening and fusion that are not directly related to the vertebral anomalies (such as in STD, where extensive posterior rib fusion occurs due to segmentation defects and extreme shortening of the thoracic vertebral column).

External links

• GeneReviews/NIH/NCBI/UW entry on Spondylothoracic Dysostosis known as Jarcho-Levin syndrome when it occurs in Puerto Ricans of Spanish descent