The Currarino syndrome is an autosomal dominant form of hereditary sacral dysgenesis that classically consists of the triad of sacral malformation, presacral mass, and anorectal malformations. However, other features include neonatal-onset bowel obstruction, chronic constipation, recurrent perianal sepsis, renal/urinary tract anomalies, female internal genital anomalies, tethered spinal cord, and anterior meningocele. There is marked inter- and intrafamilial variability, and up to 33% of patients are asymptomatic (summary by Wang et al., 2006).

Sacral defect with anterior meningocele (SDAM) is a form of caudal dysgenesis. It is present at birth and becomes symptomatic later in life, usually because of obstructive labor in females, chronic constipation, or meningitis. Inheritance is autosomal dominant (Chatkupt et al., 1994). Welch and Aterman (1984) gave a population frequency of 0.14%. Caudal dysgenesis syndrome and caudal regression syndrome are broad terms that refer to a heterogeneous constellation of congenital caudal anomalies affecting the caudal spine and spinal cord, the hindgut, the urogenital system, and the lower limbs. Approximately 15 to 25% of mothers of children with caudal dysgenesis have insulin-dependent diabetes mellitus (222100) (Lynch et al., 2000). See also Currarino syndrome (176450), a similar disorder caused by mutation in the HLXB9 gene (142994) on chromosome 7q36. Currarino syndrome classically comprises the triad of hemisacrum, anorectal malformation, and presacral mass. However, Currarino syndrome also shows phenotypic variability: Lynch et al. (2000) stated that there is variable expressivity of clinical features and that some patients with Currarino syndrome are asymptomatic. Kochling et al. (2001) found the complete triad of Currarino syndrome in only 8 of 23 patients with mutations in the HLXB9 gene, These reports suggest that some patients previously reported as having forms of sacral agenesis, including SDAM, may have had Currarino syndrome and vice versa. See also spina bifida (182940), which can be seen in some patients with sacral agenesis or caudal regression syndrome and may be etiologically related.