Discordance for anomalous pancreaticobiliary ductal junction and congenital biliary dilatation in a set of monozygotic twins.

A pair of monozygotic twins, 2-year-old Japanese girls, discordant for both anomalous pancreaticobiliary ductal junction and congenital biliary dilatation, are reported. The pathogenesis of the disease is discussed in relation to the occurrence of discordant monozygotic twins.     

Hemivertebra in monozygotic twins.

STUDY DESIGN: A case report. OBJECTIVES: To report and discuss a case of thoracic hemivertebra in monozygotic twins. SUMMARY OF BACKGROUND DATA: The etiology of congenital scoliosis remains unclear. Both a genetic basis and environmental influences have been postulated. A few isolated reports of discordant spinal anomalies in twins exist. METHODS: Clinical examination and plain radiograph evaluation were performed on female monozygotic twins with congenital scoliosis secondary to thoracic hemivertebra. RESULTS: Congenital thoracic scoliosis was documented in both of a set of monozygotic twins. CONCLUSIONS: To the authors' knowledge, this is the first report of similar congenital vertebral abnormalities in identical twins in the English literature.     

Hirschsprung's disease discordant in monozygotic twins: a study of possible environmental factors in the production of colonic aganglionosis.

The occurrence of Hirschsprung's disease, with histologically verified colonic aganglionosis, in only 1 of 2 prematurely born and presumed identical (monozygotic) twins is reported. The occurrence of monozygotic twinning was supported by the observed sharing of a single and common placenta and by ABO and HLA identity of peripheral blood erythrocytes and leukocytes. The affected twin was of a slightly lower birth weight and experienced early respiratory distress, necrotizing enterocolotis, and more prolonged umbilical artery catheterization (no encountered in the unaffected twin). This, to the authors' knowledge, is the first reported occurrence of Hirschsprung's disease discordant in monozygotic twins. The literature relating to genetic and environmental factors in clinical and experimental colonic aganglionosis is reviewed and speculation is presented regarding the occurrence of colonic aganglionosis discordant in monozygotic twins as reported here.     

Discordant Hirschsprung's disease in monozygotic twins

Two pairs of twins are being reported where monozygocity was supported by the observed sharing of a single and common placenta and by ABO and HLA identity. Only one of each pair of twins was affected by long-segment Hirschsprung's disease; the other twins were entirely normal. Discordant Hirschsprung's disease in monozygotic twins is very rare. The etiology in such cases is influenced by genetic or by environmental intrauterine factors rather than by postnatal influences, as suggested elsewhere.     

An antegrade technique for ablation of posterior urethral valves

Complications after transurethral ablation of posterior urethral valves frequently are iatrogenic because of urethral injury resulting in stricture or sphincteric incontinence. Smaller instrumentation and improved optics have made primary valve destruction safer and more reliable. The concept of early neonatal vesicostomy with delayed transurethral valve ablation allows maximal upper tract protection as well as somatic and urethral growth. This approach further reduces the possibility of urethral or sphincteric injury. We report our technique of antegrade incision of posterior urethral valves per vesicostomy, combining the advantages of early optimal neonatal vesicostomy drainage, avoidance of any anterior urethral instrumentation, and a technically easier, reliable and safe approach to posterior urethral valve destruction.     

Mirror-image trigger thumb in dichorionic identical twins

The congenital vs acquired etiology of pediatric trigger thumb is the subject of considerable debate. Existing case reports of bilateral presentation in identical twins and first-degree familial association support the congenital hypothesis. However, prospective studies have yet to report a neonate presenting with this anomaly at birth. This article describes the first known set of dichorionic, monozygotic identical twins with unilateral trigger thumbs, affecting contralateral (mirror-image) hands and with asynchronous age at presentation (11 months and 18 months, respectively).Pediatric trigger thumb is caused by a mismatch between the flexor pollicis longus tendon and its A1 synovial pulley. Four sets of twins have been previously reported in the literature with trigger thumb. Of these, 3 sets were monozygotic twins who had bilaterally affected thumbs. Together with the absence of trauma, a congenital etiology was suggested. The fact that pediatric trigger thumb is generally seen several months after birth was felt to be due to infants holding their thumbs clutched in their palms until 6 months. However, no confirmed cases of trigger thumb have been diagnosed at birth in several large prospective studies of newborns.In the current case, the asynchronous presentation of unilateral trigger thumbs in identical twins does not support a solely congenital cause. Furthermore, the mirror-image presentation contradicts current embryological understanding of the temporal course of twinning and the determination of laterality. Thus, a multifactorial etiology is supported with both a genetic and acquired component affecting the development of this condition.     

Nasopharyngeal cancer in monozygotic twins: A case report and review of the role of genetics and the environment

Introduction and importanceNasopharyngeal carcinoma (NPC) is considered a rare malignant head and neck tumour. However, the importance of genetics and environmental factors in the epidemiology of NPC is still unclear. Twins represent an excellent study population for genetic epidemiology; this is especially true of monozygotic-type twins because they are genetically identical. The difference in cancer occurrence between monozygotic twins is typically interpreted as a result of possible environmental factors.Case presentation and clinical discussionWe present the first case report of monozygotic twins with NPC. The twins' significant features are homogenous presentation, tumour location (both left-sided) and identical histology; therefore, the prognoses may be similar. Environmental factors could not be addressed in these twins because they shared the same background, and at the same time, they had no potential known contributing factors.ConclusionHaving one of the twins affected is a strong and easily recognisable risk factor for developing NPC in the other. This strong association suggests the need for regular screening of the second twin for early diagnosis of NPC.     

Posterior urethral valves in patients with Down syndrome

Renal and urological anomalies in Down syndrome (DS) have received little attention compared with the nephrourological findings described in other chromosomal abnormalities. Renal hypoplasia, hydroureteronephrosis, ureterovesical and ureteropelvic junction obstruction, and vesicoureteral reflux, but not posterior urethral valves, have been associated with DS. We report the occurrence of posterior urethral valves in three male infants with DS at a single institution. All had multiple urological procedures for correction or palliation of obstruction. Children with DS may have an increased risk for developing posterior urethral valves and obstructive uropathy. Furthermore, they may also develop chronic renal failure secondary to posterior urethral valves. Therefore, we suggests that infants with DS be screened with ultrasonography for renal and urological abnormalities early in life and, if abnormal, a contrast voiding cystourethrogram be performed to rule out posterior urethral valves or other bladder or urethral abnormalities. A review of the renal and urological anomalies in DS reported in the literature since 1960 is presented.     

PRENATAL DIAGNOSIS OF POSTERIOR URETHRAL VALVES IN SIBLINGS

Posterior urethral valves are an important cause of obstructive uropathy in the newborn. The diagnosis may be suspected on prenatal ultrasonography, the consistent finding being bilateral ureterohydronephrosis together with a thick-walled, persistently full bladder in a male fetus. There may also be variable degrees of oligohydramnios. This paper reports the case of siblings in whom posterior urethral valves were recognized prenatally. The first child progressed well after appropriate surgical management, but the second died within 24 h of birth.     

CONGENITAL BULBAR URETHRAL STRICTURES OCCURRING IN THREE BROTHERS

Three brothers with identical congenital bulbar urethral strictures are presented. These rare lesions are distinct from posterior urethral valves although the exact embryological origin is uncertain. The current literature is also reviewed.     

The anatomy and embryology of posterior urethral valves

PURPOSE: We reviewed the literature to better elucidate the history behind our understanding of the anatomy, classification and embryology of posterior urethral valves. MATERIALS AND METHODS: A directed MEDLINE literature review of the anatomy, classification and embryology of posterior urethral valves was performed. An effort was made to focus on the most frequently cited historical articles as well as those including detailed anatomical analyses of fetal specimens. Also included was the analysis of a specimen obtained at our institution in a novel manner that to our knowledge has not been previously described in the literature with respect to the anatomy of posterior urethral valves. RESULTS: The precise origins regarding the anatomy and embryology of posterior urethral valves remain undefined. However, the literature is abundant in theories regarding the origin of posterior urethral valves, based primarily on small uncontrolled series or case reports. There are a limited number of reports of the anatomy of posterior urethral valves in methodical fashion using reproducible scientific techniques such as histopathology. These reports are invaluable for providing a foundation of how to properly study and define the origins of posterior urethral valves. CONCLUSIONS: Elucidating this most fundamental feature of a congenital condition central to the practice of pediatric urology is essential. More well designed studies specifically with this goal in mind are necessary. Incorporating new reconstructive imaging modalities may assist us in pinpointing the elusive origins of the embryology and anatomy of posterior urethral valves.     

Mirror imaging cleft lip in monozygotic twins

Although genetic and environmental factors have been found to effect the occurrence of cleft lip, many aspects of its etiology are still unclear. The value of the studies on monozygotic twins has been accepted by many authors. Especially the concordant anomalies gain importance in the monozygotic twins who are influenced by the same genetic and environmental factors. Here we present a case of monozygotic twins with cleft lip deformities showing mirror image concordance.     

Familial glioma: a report of glioblastoma in identical twins and oligo-astrocytoma in siblings

The authors report two pairs of siblings who had intracranial gliomas. One pair of identical twins had glioblastomas and two siblings had mixed oligo-astrocytomas. Genetic influences in the aetiology of glioma are discussed.     

Case report on testicular tumors in non-twin siblings

A case report of testicular tumors in non-twin siblings is presented. A 42-year-old male was admitted to Kansai Electric Power Hospital with the complaint of swelling of the left scrotal contents. Left radical orchiectomy was performed with the diagnosis of a left testicular tumor. Histological examination revealed a seminoma of the left testis. Fifteen years later, his 43-year-old younger brother was admitted to Osaka University Hospital with the complaint of painless swelling of the left scrotal contents. Left radical orchiectomy was carried out with the diagnosis of a left testicular tumor. Histological examination showed a seminoma of the left testis. The former patient had a history of a scrotal trauma, but there was no history of orchitis or cryptorchism in these two siblings. To our knowledge, there have been reported 44 sets of testicular tumors in siblings. Eleven of these sets appeared in twins, while the other 33 sets were described in non-twin siblings. We discussed the 45 cases including our case of testicular tumors in siblings.     

Posterior urethral valves: prenatal diagnostic signs and outcome

INTRODUCTION: Urethral valves can be of enormous clinical importance. Both the prognosis for an affected fetus and the indication for a prenatal therapeutic intervention depend to a high degree on the accuracy of the prenatal diagnosis. PATIENTS AND METHODS: The sonographic findings and the results of the postnatal diagnostic workup of 24 boys treated for urethral valves in our institute are analyzed in the present paper. RESULTS: Out of a group of 900 children, diagnosed prenatally as having urinary tract anomalies, the postnatal diagnostic workup revealed 24 boys suffering from posterior urethral valves. The combination of megacystis, oligohydramnios, and bilateral renal abnormalities was present in 3 boys, and it was only in these cases that urethral valves were correctly identified as the underlying pathology. The largest group (n = 16) of these fetuses presented with bilateral hydronephrosis with and without megaureter. Megacystis in any combination with other findings was detected only in 4 patients. Oligohydramnios as a sign of impaired renal function was observed in four pregnancies. Four children suffered postnatally from beginning renal insufficiency. Eight infants (33%) required some form of respiratory support. This group included the 4 newborns with oligohydramnios during the pregnancy. CONCLUSIONS: Posterior urethral valves represent a rare but severe congenital malformation. They can disrupt the development of the entire urinary tract and may be life-limiting to the affected boy. Only rarely, however, are they manifested as the complete pathological picture on prenatal ultrasound. In most cases, bilateral impairment of the fetal renal development suggests severe subvesical obstruction. Thus in cases with bilateral renal impairment on prenatal ultrasonography, posterior urethral valves are to be excluded postnatally. Oligohydramnios is a predictor of a poor outcome of the renal function.     

Renal tubular dysgenesis in twins

In a fetal autopsy series, we have explored the occurrence of renal tubular dysgenesis in twins. Renal tubular dysgenesis was found exclusively among those monozygotic twins with evidence of twin transfusion syndrome, particularly in those donor twins with oligohydramnios and growth restriction. We infer that hypotension in the donor twin of the twin transfusion syndrome pair is responsible for the failure of proximal convoluted tubule differentiation, and the disturbance of renal function is manifested as oligohydramnios prenatally, and either oliguria or tubular dysfunction postnatally. Received February 7, 1997; received in revised form and accepted December 15, 1997     

Emergency treatment and long-term follow-up of posterior urethral valves

Posterior urethral valves have a broad spectrum of clinical severity determined by the degree and reversibility of the long stepwise sequence of secondary pathology. Neonatal azotemia and severe bilateral reflux are particularly important negative prognostic factors. In the mild cases, valve ablation with or without delayed reconstruction is good therapy. In the very severe cases, our interpretation of all the clinical and experimental information now available suggests that the time interval and the level of decompression are extremely important. Achievement of consistent low caliceal pressure without stasis and infections should be achieved as soon as possible. We do not agree with the philosophy of "valve ablation and wait and see" for secondary reconstruction as applied to the severe cases. An analogous philosophy would be treating all respiratory infections as upper respiratory infections and applying aggressive appropriate therapy for pneumonia only if the patient does not respond clinically. However, all controversy aside, the management of neonatal infants with posterior urethral valves remains a difficult and challenging problem for us all. The real challenge will be to improve published management results to the point that the family faced with decisions regarding an in utero diagnosis of posterior urethral valves will have enough hope to continue the pregnancy.     

Popliteal artery entrapment syndrome of the monozygotic twin--a case report and pathogenetic hypothesis

A 22 year old Japanese man with popliteal artery entrapment syndrome in which both popliteal arteries were segmentally occluded and deviated medially, underwent surgical treatment by grafting and patching with autologous veins. His identical co-twin was also found to have a less severe form of popliteal artery entrapment syndrome. This is the first report of popliteal artery entrapment syndrome presenting in a pair of monozygotic twins and the concordance of the syndrome suggests that genetic factors may play a part in the development of this rare syndrome.     

Nephrolithiasis in identical twins: the impact of nature vs nurture

OBJECTIVE: To assess possible underlying metabolic abnormalities in three sets of monozygotic twins, to evaluate the interplay among the factors of kidney stone formation, a complex multifactorial process influenced by environmental, genetic and anatomical factors. PATIENTS AND METHODS: Three sets of identical twins with either cystine or calcium oxalate stones were identified. Demographic data, medical histories and the results of 24-h urine testing, with samples collected on self-selected diets, were reviewed and analysed. RESULTS: The cystinuric twins had very similar cystine excretion rates, while stone activity was significantly more pronounced in one. Metabolic abnormalities were concordant in one set of twins with calcium oxalate stones, both being hypercalciuric and hyperuricosuric. However, metabolic abnormalities were discordant in the other pair, one twin with hypercalciuria and the other with hypocitraturia. Two of the three pairs had low urinary volume. CONCLUSIONS: These results support previous observations that environmental, genetic and potentially, anatomical factors play roles in kidney-stone formation. Additional controlled studies of monozygotic stone-forming twins might help to define the interplay between environmental and genetic factors, and allow the identification of susceptibility genes involved in stone generation.     

Popliteal artery entrapment syndrome of the monozygotic twin —A case report and pathogenetic hypothesis—

A 22 year old Japanese man with popliteal artery entrapment syndrome in which both popliteal arteries were segmentally occluded and deviated medially, underwent surgical treatment by grafting and patching with autologous veins. His identical co-twin was also found to have a less severe form of popliteal artery entrapment syndrome. This is the first report of popliteal artery entrapment syndrome presenting in a pair of monozygotic twins and the concordance of the syndrome suggests that genetic factors may play a part in the development of this rare syndrome.