Caudal regression syndrome (Currarino syndrome) with chromosom mutation 9

Atypical caudal regression syndrome with lumbar agenesis, hypoplastic sacrum without sacroiliac joints in the eastern Democratic Republic of Congo: a case report

The agenesis of any segment of the lower spinal column referred to as "caudal regression syndrome" (CRS) is a rare congenital defect of the spine. This malformation is characterized by the absence of some or the entire lumbosacral vertebral segment. Etiological factors remain unknown. We report an atypical caudal regression syndrome with lumbar agenesis, disconnected from the remaining hypoplastic sacrum, in the Eastern part of the Democratic Republic of Congo (DRC).An 11-month-old female infant with no particular fetal or maternal history presented limb weakness with flexed knees and flanges in the popliteal fossae, sphincter atony, and a sensation of emptiness on palpation in the lumbosacral region. A 3D CT scan of the spine showed the absence of the lumbar spine and disconnection of the upper segment of the thoracic spine from the hypoplastic sacrum. We noted also the absence of the sacroiliac joints bilaterally and an unusual trigonal shape of the iliac bones. MRI and sonographic examination are required in the investigation of the disease. The management is multidisciplinary and depends upon the degree of the defect. Spine reconstruction has proven to be a valuable management technique but has many complications. We wanted to draw the medical world's attention to the existence of this extremely rare malformation in the east of the Democratic Republic of Congo, a mining area.

Case report: Sacral agenesis in two boxer dogs: clinical presentation, diagnostic investigations, and outcome

Two boxer dogs from the same litter were presented at 3 months of age for urinary and fecal incontinence. Both dogs had an abnormal tail consisting of a small stump, an atonic anal sphincter, and absent perineal reflex and sensation. Neurological evaluation was indicative of a lesion of the cauda equina or sacral spinal cord. Radiology and CT scan of the spine displayed similar findings in the two dogs that were indicative of sacral agenesis. Indeed, they had 6 lumbar vertebrae followed by a lumbosacral transitional vertebra, lacking a complete spinous process, and a hypoplastic vertebra carrying 2 hypoplastic sacral transverse processes as the only remnant of the sacral bone. Caudal vertebrae were absent in one of the dogs. On MRI, one dog had a dural sac occupying the entire spinal canal and ending in a subfascial fat structure. In the other dog, the dural sac finished in an extracanalar, subfascial, well-defined cystic structure, communicating with the subarachnoid space, and consistent with a meningocele. Sacral agenesis-that is the partial or complete absence of the sacral bones-is a neural tube defect occasionally reported in humans with spina bifida occulta. Sacral agenesis has been described in human and veterinary medicine in association with conditions such as caudal regression syndrome, perosomus elumbis, and Currarino syndrome. These neural tube defects are caused by genetic and/or environmental factors. Despite thorough genetic investigation, no candidate variants in genes with known functional impact on bone development or sacral development could be found in the affected dogs. To the best of the authors' knowledge, this is the first report describing similar sacral agenesis in two related boxer dogs.

Congenital aphallia associated with congenital urethrorectal fistula: A rare case report

RATIONALE

Aphallia is an extremely rare congenital malformation of unknown cause, with few reports in the literature. It is usually associated with other urogenital and gastrointestinal anomalies and is believed to be a result of either the absence of a genital tubercle or chromosome polymorphism. Herein, we describe an extremely rare case of congenital aphallia with congenital urethrorectal fistula and describe our treatment for this patient.

PATIENT CONCERNS

An 8-year-old boy was brought to our hospital by his parents because of congenital absence of the penis. The child was male per karyotype and had excess heterochromatin on chromosome 9 (46 XY with 9 qh+). No urethral orifice was identified, and urine passed rectally since birth; thus, urinary tract outlet obstruction led to urine reflux from the anus to the epididymis for a long time. The boy had to be placed on prophylactic antibiotics because he developed urinary tract infection and epididymitis almost every day.

DIAGNOSIS

Congenital aphallia (46 XY normal male karyotype) associated with congenital urethroretal fistula.

INTERVENTIONS

We performed urethral exteriorization via perineal urethroplasty and urethrorectal fistula repair. The parents approved for phallic reconstruction when the boy reached puberty.

OUTCOME

A new external urethral orifice was created on the lower scrotum. The urinary reflux was corrected, and the epididymitis symptoms disappeared. The urethral fistula was then closed. At 8 months follow up, the patient was no longer on antibiotics and had no symptoms of urinary tract infection or epididymitis.

CONCLUSIONS

Compatible treatment should be adopted to address urinary tract drainage and infection. Management requires a stepwise approach to address needs as they arise. Neophalloplasty should be performed by an experienced team in early adolescence.

Currarino syndrome: a comprehensive genetic review of a rare congenital disorder

Background

The triad of a presacral mass, sacral agenesis and an anorectal anomaly constitutes the rare Currarino syndrome (CS), which is caused by dorsal–ventral patterning defects during embryonic development. The major causative CS gene is MNX1, encoding a homeobox protein.

Main body

In the majority of patients, CS occurs as an autosomal dominant trait; however, a female predominance observed, implies that CS may underlie an additional mode(s) of inheritance. Often, the diagnosis of CS is established solely by clinical findings, impacting a detailed analysis of the disease. Our combined data, evaluating more than 60 studies reporting patients with CS-associated mutations, revealed a slightly higher incidence rate in females with a female-to-male ratio of 1.39:1. Overall, MNX1 mutation analysis was successful in only 57.4% of all CS patients investigated, with no mutation detected in 7.7% of the familial and 68% of the sporadic patients. Our studies failed to detect the presence of an expressed MNX1 isoform that might explain at least some of these mutation-negative cases.

Conclusion

Aside from MNX1, other genes or regulatory regions may contribute to CS and we discuss several cytogenetic studies and whole-exome sequencing data that have implicated further loci/genes in its etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01799-0.