Caudal regression syndrome, or sacral agenesis (or

hypoplasia Hypoplasia (from Ancient Greek ὑπo- ''hypo-'' 'under' + πλάσις ''plasis'' 'formation'; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ.sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...

), is a rare birth defect. It is a

congenital disorder A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...

in which the

fetal development Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal devel ...

of the lower spine—the caudal partition of the spine—is abnormal. It occurs at a rate of approximately one per 60,000 live births.Medline Plus. Caudal Regression Syndrome.https://medlineplus.gov/genetics/condition/caudal-regression-syndrome/#frequency Some babies are born with very small differences compared to typical development, and others have significant changes. Most grow up to be otherwise typical adults who have difficulty with walking and incontinence.

Signs and symptoms

This condition exists in a variety of forms, ranging from partial absence of the

tail bone The coccyx (plural, : coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horse anatomy, horses. In tailless primates ( ...

regions of the spine to absence of the lower vertebrae, pelvis and parts of the thoracic and/or lumbar areas of the spine. In some cases, where only a small part of the spine is absent, there may be no outward sign of the condition. In cases where more substantial areas of the spine are absent, there may be fused, webbed or smaller lower extremities and paralysis. Bowel and bladder control is usually affected.

Cause

The condition arises from some factor or set of factors present during approximately the 3rd week to 7th week of fetal development. Formation of the sacrum/lower back and corresponding nervous system is usually nearing completion by the 4th week of development. Due to abnormal gastrulation, the mesoderm migration is disturbed. This disturbance results in symptoms varying from minor lesions of the lower vertebrae to more severe symptoms such as complete fusion of the lower limbs. While the exact cause is unknown, it has been speculated that the condition has a combination of environmental and genetic causes, and that various types of the condition may have differing causes. Sacral agenesis syndrome (a type of caudal regression syndrome involving agenesis of the

lumbar spine The lumbar vertebrae are, in human anatomy, the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse p ...

, sacrum, and

coccyx The coccyx ( : coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horses. In tailless primates (e.g. humans and othe ...

, and hypoplasia of the lower extremities) is a well-established congenital anomaly associated with maternal

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

mellitus. Other causes are presumably involved, as demonstrated by the rare overall incidence of caudal regression syndrome (1:60,000) compared to diabetes; however, the condition does have a greatly increased incidence among infants born to mothers with diabetes, estimated at 1 in 350 newborns of mothers with diabetes. The dominant inherited sacral agenesis (also referred to as

Currarino syndrome Currarino syndrome is an inherited congenital disorder where either the sacrum (the fused vertebrae forming the back of the pelvis) is not formed properly, or there is a mass in the presacral space in front of the sacrum, and there are malformatio ...

) is very often correlated with a

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...

in the Hb9 (also called HlxB9) gene (shown by Sally Ann Lynch, 1995, Nature Genetics). It was previously thought to be related to

sirenomelia Sirenomelia, also called mermaid syndrome, is a rare congenital deformity in which the legs are fused together, giving the appearance of a mermaid's tail, hence the nickname. Classification Sirenomelia is classified by the skeletal structure ...

("Mermaid syndrome") but has now been determined not to be related to this condition.

Prognosis

There are four levels (or types) of malformation. The least severe indicates partial deformation (unilateral) of the sacrum. The second level indicates a bilateral (uniform) deformation. The most severe types involve a total absence of the sacrum. Depending on the type of sacral agenesis, bowel or urinary bladder deficiencies may be present. A permanent

colostomy A colostomy is an opening ( stoma) in the large intestine (colon), or the surgical procedure that creates one. The opening is formed by drawing the healthy end of the colon through an incision in the anterior abdominal wall and suturing it int ...

may be necessary in the case of

imperforate anus An imperforate anus or anorectal malformations (ARMs) are birth defects in which the rectum is malformed. ARMs are a spectrum of different congenital anomalies which vary from fairly minor lesions to complex anomalies. The cause of ARMs is unkno ...

. Incontinence may also require some type of continence control system (e.g., self-catheterization) to be utilized. The condition often impacts the formation of the knees, legs or feet that is sometimes addressed through surgery. For some with tightly webbed, bent knees or knees that are fused straight, disarticulation surgery at the knee may be a viable option to maximize mobility options. Before more comprehensive medical treatment was available, full amputation of the legs at the hip was often performed. More recently, the amputation (actually a disarticulation because no cutting of the bone is involved) is done at the knee for those who have bent knee positions and webbing between thigh and calf to enable more ease of mobility and better seating. Some children with knee disarticulation use prosthetic legs to walk. Prosthetics for children without substantial hip and trunk control is usually abandoned in favor of faster and easier wheelchair mobility as the child's weight and age increase. Children may walk on their hands and generally are able to climb and move about to accomplish whatever they need and want to accomplish. Children more mildly affected may have normal gait and no need for assistive devices for walking. Others may walk with bracing or crutches. There is typically no cognitive impairment associated with this disability. Adults with this disability live independently, attend college, and have careers in various fields. In 2012,

Spencer West Spencer West (born January 7, 1981) is an American motivational speaker and disability advocate. West became an amputee after being born with sacral agenesis. He speaks about overcoming adversity and uses social media to advocate for the disabil ...

, a man with sacral agenesis and both legs amputated, climbed

Mount Kilimanjaro Mount Kilimanjaro () is a dormant volcano in Tanzania. It has three volcanic cones: Kibo, Mawenzi, and Shira. It is the highest mountain in Africa and the highest free-standing mountain above sea level in the world: above sea level and ab ...

using only his hands. In 2021, athlete Zion Clark broke the Guinness World Record 20 m running on hands.

Society and culture

Notable people

* Zion Clark, American track athlete and wrestler, 2022 Guinness World Record holder (20 m hand sprint in 4.78 seconds) * Rebecca Dubber, New Zealand para-swimmer and Rio 2016 Paralympic bronze medalist *

Kenny Easterday Kenneth Easterday (December 7, 1973 – February 12, 2016) was an American man born with the rare disability, Caudal regression syndrome, sacral agenesis. To improve his mobility, his legs were amputated at the hip when he was six months old. Li ...

, played a fictionalized version of himself in the film ''

Kenny Kenny is a surname, a given name, and a diminutive of several different given names. In Ireland, the surname is an Anglicisation of the Irish language, Irish ''Ó Cionnaith'', also spelt ''Ó Cionnaoith'' and ''Ó Cionaodha'', meaning "descendant ...

'' *

Johnny Eck John Eckhardt Jr, (August 27, 1911 – January 5, 1991), professionally billed as Johnny Eck, was an American freak show performer in sideshows and a film actor. Born with sacral agenesis, Eck is best known today for his role in Tod Browning' ...

, American freak show performer *

Kurt Fearnley Kurt Harry Fearnley, (born 23 March 1981) is an Australian wheelchair racer, who has won gold medals at the Paralympic Games and 'crawled' the Kokoda Track. He has a congenital disorder called sacral agenesis which prevented fetal developme ...

, Australian wheelchair racer * Chloé Cooper Jones, American philosopher and author * Bobby Martin, American footballer * Kevin McKee, two-times Olympic champion and two-times world champion in sledge hockey *

Sainimili Naivalu Sainimili Naivalu (1986–2019) was a paralympic athlete and disability activist from Fiji. She represented Fiji in international wheelchair table tennis competitions and was awarded gold and silver medals. Biography Naivalu was born in 1986 ...

, Fijian wheelchair table tennis medallist and disability rights activists *

Victoria Pendergast Victoria "Tori" Pendergast (born 25 January 1991) is an Australian F58 athletics shot put competitor and LW12.1 classified Para-alpine skier. When she competed at the 2014 Winter Paralympics in Sochi, she became Australia's first female ...

, first female Australian sit-skier at Winter Paralympics *

Jessica Rogers Jessica Rogers (born 9 March 1997) is an American wheelchair basketballer, wheelchair racer and swimmer. She is also the founder of the ''International Sacral Agenesis/Caudal Regression Syndrome Association'', or iSACRA, an organization for infor ...

, American wheelchair racer and swimmer, founder and President of iSACRA (International Caudal Regression Syndrome Association) *

Rose Siggins Rose Marie Homan (December 8, 1972 – December 12, 2015), better known by her stage (and married) name Rose Siggins, was an American actress best known for her portrayal of Legless Suzi on '' American Horror Story: Freak Show''. Siggins was bor ...

, actress ('' American Horror Story: Freak Show'') *

, Mountain climber, "Man Climbs Mt. Kilimanjaro On Hands". ABC News. 22 June 2012. * Ghanim Al Muftah, a Qatari businessman, opened the 2022 Mondial ceremony as well as the 2022 Qatar Football World Cup with Morgan Freeman.

References

External links

{{Multiple abnormalities Rare syndromes Congenital disorders Skeletal disorders Sacrum Syndromes affecting the nervous system