|
In reviewing individuals with Rubinstein-Taybi syndrome (RTS), the most common genitourinary anomaly is undescended testis (UDT). However, a wide range of minor structural and functional problems of the urinary tract have
also been reported.
UNDESCENDED TESTIS
At an early stage of fetal development, the testes develop in the upper abdomen next to the kidneys. During the 7th to 9th month of gestation, the testes begin to descend through the abdominal cavity and inguinal canal
towards the scrotum. Testicular descent is believed to be necessary to produce fertile sperm, the 2-3 OC cooler temperature afforded by the scrotum appears critical in this regard. Numerous theories have been
suggested regarding the mechanisms which result in normal testicular descent, but the exact process remains unclear.
Approximately 3% of all full-term male infants are born with an undescended testis, but this figure drops to about 0.5%-0.7% by the age of six months. Thereafter, spontaneous descent is basically non-existent and surgery
(orchidopexy) is usually recommended between 6 to 12 months of age. There are strong clinical and experimental lines of evidence to suggest that a testis which remains undescended after one year of age has a very limited
capability to produce functional sperm after puberty. Since hormonal function is preserved, even in undescended testicles, pre-pubertal boys are candidates for surgical repair of this condition. There is an
increased risk of cancer development in UDT, therefore post-pubertal boys are best managed by removal of the undescended testis, as long as the other testis is normal.
Children with bilateral UDT may be handled slightly differently. For this group, a course of human chorionic gonadotropin (HCG) can be considered, since children with this condition may have a hormonal imbalance. If
there is no response to therapy, surgery is recommended.
Undescended tests were reported in 78% (Hennekam, 1990)1 to 100% (Stevens, 1990) 1 of males with RTS. Hennekam (1990) stated that 86% of boys had bilateral UDT. Stevens (1990) reported that 81%
of RTS patients required orchidopexy. The management of the undescended t in boys with RTS is unaffected by the presence of the latter condition and is performed as in otherwise normal boys. Parents of the infant
male with RTS and UDT should be prepared for the fact that their child will require orchidopexy within the first year of life.
UROLOGIC ANOMALIES
Urologic anomalies have been reported in 28% (Stevens, 1990) 2 to 52% (Rubinstein, 1990) 3 of children with RTS. The majority are comprised or urinary tract infections and minor anomalies of the upper urinary tract. The latter are usually a double (or, bifid) ureter, or a condition known as vesicoureteral reflux – the reflux of urine in the wrong direction from the bladder to the kidney. Treatment of vesicoureteral reflux usually requires long-term antibiotic prophylaxis to prevent urinary tract infections and deterioration of renal function. Currently, we recommend that all children with Rubinstein-Taybi syndrome are screened with a renal ultrasound and voiding cystogram.
Constipation has been reported in 40% to 60% (Hennekam, 1990) 1 of children with RTS. Since constipation has the adverse effect of causing frequent urinary tract infections, we recommend an aggressive approach in
the treatment of constipation. This should include a high fiber diet, adequate fluid intake, a stool softener or mild laxative if necessary.
1.) Hennekam RCM, Van Den Boogaard MJ, Sibbles BJ, et al. Rubinstein-Taybi syndrome in the Netherlands. Am J Med Genet Suppl 1990;6:17-29.
2.) Stevens CA, Carey JC, Blackburn BL. Rubinstein-Taybi syndrome: a natural history study. Am J Med Genet Suppl 1990;6:30-7.
Rubinstein JH. Broad thumb-hallux (Rubinstein-Taybi syndrome. 1957-1988. Am J Med Genet Suppl 1990;6:1-16.
|
