Splenogonadal Fusion With Limb Defects And Micrognathia

Description

Splenogonadal fusion (SGF) is a rare congenital anomaly of abnormal fusion between the spleen and the gonad or the remnants of the mesonephros. In 'continuous SGF,' there is a cord-like connection between the 2 organs, whereas in 'discontinuous SGF,' there is fusion of accessory splenic tissue and the gonad without a distinct structural connection to the spleen itself. Forty-eight percent of individuals with continuous SGF have additional malformations, compared to 9% of those with discontinuous SGF (McPherson et al., 2003).

Clinical Features

Putschar and Manion (1956) first proposed that fusion of the spleen and gonad with accompanying ectromelia was a specific entity. Hives and Eggum (1961) reported a ninth case. Seven were stillborn or died in infancy; the eighth died at age 10. Their patient was 15 years old. Pauli and Greenlaw (1982) reported a 10-year-old boy with tetramelic limb deficiencies, splenogonadal fusion, and mild mandibular and oral abnormalities (micrognathia, multiple unerupted teeth, crowding of the upper incisors, and deep, narrow, V-shaped palate without cleft). They reviewed 14 cases in the literature. The extent of the terminal transverse hemimelia was variable. They suggested that the disorder is not 'invariably lethal.' This still may be a genetic lethal; procreation by an affected person has not been reported. Of the 15 cases, only 1 was female.

Bonneau et al. (1999) reported 5 new cases of what they called splenogonadal fusion limb defect (SGFLD) syndrome and reviewed the 25 cases reported since 1989. Most cases had a combination of severe limb and oromandibular defects, suggesting that SGFLD may be related to the broader group of Hanhart complex. In addition, several cases had limb malformations and facial anomalies, which suggested that SGFLD overlaps with both femur-fibula-ulna dysostosis (228200) and femoral-facial syndrome (134780). A vascular disruptive event, occurring between the fifth and seventh weeks of gestation, could explain the limb defects, mandibular hypoplasia, and fusion of the spleen to the gonad observed in SGFLD. All reported cases were sporadic.

McPherson et al. (2003) reported a 19-week male fetus with SGFLD. Postmortem analysis showed epicanthal folds, depressed nasal bridge, posteriorly angulated ears, and micrognathia. The upper lip and palate were intact. The right lower limb was a single, short, distally pointed leg bone with absence of 1 mesomelic leg bone of the foot and ankle; the right femur was bowed. The left lower limb was a single bent bone, possibly a tibia, with a single metatarsal and rudimentary digit. The upper limbs were unremarkable. Internal examination showed bilobed lungs, tetralogy of Fallot, malrotation of the small bowel, anal atresia, bilateral renal agenesis, absent urinary bladder, and enlarged adrenal glands. There was a cleft of the distal end of the spleen and a fibrous connection to the left testis. External genitalia were absent, but there was a midline 0.2-cm long skin tag resembling a penis. Chromosomal analysis showed a normal 46,XY karyotype. The authors postulated a developmental defect during blastogenesis, with earlier occurrence resulting in more severe manifestations. McPherson et al. (2003) stated that over 30 cases of SGFLD and 145 cases of SGF had been reported.