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Editor—True agonadism, characterised by the absence of gonads in both XY and XX patients, is a rare, mostly sporadic, and isolated condition. Its association with diaphragmatic hernia seems to be extremely rare and has always been described associated with multiple congenital malformation (MCA) syndromes of unknown origin. Sex reversal and diaphragmatic hernia have been described once with a heterozygous WT1mutation in a sporadic case.1 The association of normal feminisation, absent gonads, and diaphragmatic hernia in two XY sibs without any other malformation suggested other diagnostic possibilities. Since further investigations did not find any chromosomal or known genetic cause for this familial sex reversal syndrome, we suggest that these cases could represent a new sex reversal syndrome, which could be either autosomal recessive or X linked, and may result from either unreported mutations ofWT1 or anomalies of other developmental genes.
The proband (fig 1, II.4) is the fourth child of non-consanguineous, healthy parents with an unremarkable family history. Their first child (II.1), a girl born at term in 1989, died of severe respiratory distress at 2 days of age after surgery for a left diaphragmatic hernia. She was of normal size (weight 3200 g, 50th centile) and according to the paediatricians not dysmorphic. No additional malformation was found at necropsy apart from the large left diaphragmatic hernia and a single umbilical artery. Chromosomal analysis was not performed. Two subsequent pregnancies resulted in normal, healthy, male children (II.2, II.3).
At 34 weeks' gestation of the fourth pregnancy, ultrasonography detected dextrocardia owing to a left diaphragmatic hernia involving the stomach, left lobe of the liver, and numerous intestinal loops. Chromosomal analyses were performed on both lymphocytes from fetal blood and fibroblasts from amniotic fluid. They were normal male: 46,XY. Delivery was spontaneous at 37 weeks' gestation. Neonatal measurements were within normal limits (weight 2370 g, 10th centile, OFC 31 cm, 10th centile). Intubation was performed immediately after birth and the infant was transferred to the intensive care unit. HFO and NO treatments were given. Apart from the respiratory distress syndrome, the clinically female infant was normal except for bilateral membranous syndactyly of the second and third toes. This was absent in all three sibs but present to a lesser degree in her father. Cardiac and abdominal ultrasonography were normal. The diaphragmatic hernia was surgically repaired at 2 weeks of age, when an almost total absence of the left diaphragm was noted. This required the fitting of a Goretex® plate. The subsequent course was favourable and ventilatory support was discontinued at 1 month of age. At 9 months the patient was in good health; weight was 6 kg (−2 SD), height 66 cm (−1 SD), OFC 43 cm (−1 SD), and neuromotor development was normal.
Further investigations were performed in the proband who had completely feminised external genitalia, a normal male karyotype, severe diaphragmatic hernia, and whose sister had died of diaphragmatic hernia. Cholesterol and 7OH cholesterol were normal so that Smith-Lemli-Opitz syndrome (MIM 270400) could be excluded. Skeletalx rays showed somewhat curved clavicles but no anomaly that could indicate campomelic dysplasia (MIM 114290). Hormonal profile in the neonatal period showed very low testosterone (0.21 ng/ml, normal 2-4 ng/ml) and dehydrotestosterone (0.04 ng/ml), with normal FSH (1.8 IU/l) and LH (1.1 IU/l) levels, as seen in both complete XY gonadal dysgenesis and agonadism. Ultrasonography of the visceral organs showed the presence of an apparently normal uterus. Pelvic endoscopy was performed at 6 months of age and confirmed the presence of a normal uterus and fallopian tubes; however, no gonads were found, not even in an ectopic position. High resolution G banding chromosome analysis confirmed the normal male karyotype; in particular no anomalies were observed in the regions of localised or putative sex determining genes, such as Yp11.3 (SRY), Xp21.3 (DSS/DAX-1), 11p13 (WT1), 17q24 (SOX9), 9p,2 3 or 10q.4 SRY was present and PCR analyses of both the promoter and the unique exon showed that they were present and of normal size. Furthermore, fluorescent in situ hybridisation (FISH) of the Y chromosome performed on paraffin preserved tissue from the dead sib detected retrospectively the presence of a Y chromosome. SRY analyses could not be performed because of the small amount of tissue preserved, and it was not possible to study retrospectively the internal genitalia of this normally feminised infant.
As diaphragmatic hernia has been described in one case of Denys-Drash syndrome (DDS, MIM 194080),1 renal function was carefully investigated in the proband (whose renal ultrasonography was normal) and was found to be normal. Moreover, renal tissue of the dead sister was re-examined and found to be normal. Finally, in the proband no anomaly was found in exons 7, 8, or 9 of theWT1 gene, which is responsible for DDS and Frasier syndrome (FS, MIM 136680).
Here we report two sibs with a normal male karyotype and diaphragmatic hernia. Clinical and laboratory investigations of sex reversal established the diagnosis of true agonadism, which is a rare, mostly sporadic condition characterised by the absence of gonadal structure. Agonadism has almost always been diagnosed in cases with a normal male (XY) karyotype, female external genitalia, and absence of extragenital anomalies. However, the condition could have been overlooked in karyotypically female patients because of the absence of sex reversal. In XY patients, agonadism has to be differentiated from XY pure gonadal dysgenesis (Swyer syndrome resulting fromSRY mutations (MIM 306100)), in which the gonads are reduced to streaks but are present, and both external and internal genitalia are normal female. In XY patients, agonadism was termed embryonic testicular regression syndrome5 6because, from an embryological point of view, it may be the result of secondary precocious regression rather than true agenesis of the primary undifferentiated gonads. Thus, early testicular tissue action (anti-Müllerian hormone (AMH) and testosterone) could explain the range of virilisation in some agonadal XY patients. Because of the few familial cases of XY embryonic testicular regression syndrome,7-9 genetic determinism has been suggested.
Agonadism has seldom been observed with an XX chromosomal constitution in either sporadic (n=1)10 (n=2)11 or familial cases (both XY and XX affected sibs of consanguineous parents).12 External genitalia were normal female in all five patients, but Müllerian ducts were either absent,10hypoplastic,12 or normal,11 whereas no transient testicular anti-Müllerian effect can have acted in these XX patients. Thus, the question is raised of the involvement of autosomal genetic factors maintaining both gonads and Müllerian ducts (the latter independently of AMH action).
On the other hand, agonadism has also been described associated with variable extragenital anomalies in both sporadic13-19 and familial cases20-22 (table 1), of which one sporadic15 and one familial20 21 cases were also associated with diaphragmatic hernia. However, the remaining features in these patients are sufficiently different from those we describe to exclude comparison. In the patient described by Oyeret al,15 Müllerian derivative defects and bicuspid aortic valve were observed. In the sibs born to unrelated parents described by Sorgo et al 20 and Kennerknecht et al,21 Müllerian ducts were present although rudimentary, and diaphragmatic hernia was associated with a heart defect in a patient with an XY chromosomal constitution, whose XX sib presented with omphalocele, heart defect, and cleft palate.
Diaphragmatic hernia and sex reversal has been described associated with multiple malformations in three unrelated phenotypic girls with a normal XY karyotype.23 24 However, the multiple associated malformations, cyanotic complex heart defect (n=2),23 hypoplastic left ventricle, ectopic spleen, and horseshoe kidney (n=1),24 and above all the presence of testis tissue are sufficiently different from our observations to distinguish these conditions
We also looked for WT1 mutations (which were first described in patients with Wilms tumour,25 26 then in DDS syndrome,26 and more recently in Frasier syndrome27 28), because of the description of a WT1 point mutation (arg 366 his) in a phenotypic girl with a normal male karyotype, a large left posterolateral diaphragmatic hernia, and features of DDS (dysgenetic ovaries, double uterus, double vagina, and severe glomerulopathy), who died at 5 hours of age from respiratory distress.1Furthermore, transgenic mice with a homozygousWT1 deletion consistently have diaphragmatic hernia and heart defects besides their urogenital malformations,29 although noWT1 mutation has been found in patients with isolated diaphragmatic hernia.30 WT1 is expressed in abdominal and lung mesothelium and encodes four isoforms of zinc finger transcriptional factors that could regulate several genes involved in the development of the diaphragm as well as those implicated in sex determination and differentiation, such as SRY,AMH, and the androgen receptor genes.31 Our patient did not fit all the diagnostic criteria for either DDS or FS; she had agonadism rather than gonadal dysgenesis, her Müllerian structures were normally developed while they are often hypoplastic or absent in DDS or FS, she has not presented any renal anomalies up to the age of 1 year, and no mutation has been found in WT1 exons 7, 8, or 9. However, the absence of identified gonads could be an extreme form of gonadal dysgenesis,32 testicular regression could have been precocious enough to prevent AMH secretion, and renal dysfunction owing to WT1 mutations could appear later (as seen in FS). Since, to our knowledge, no other familial cases of true agonadism associated with diaphragmatic hernia have been published, and since we did not find WT1mutations known to be implicated in DDS and FS syndromes in our patient, we suggest that such cases could represent a new sex reversal syndrome that could be either autosomal recessive or X linked, and result from either unreported mutations ofWT1 or anomalies of other developmental genes.