Low Maternal DLK1 Levels at 26 Weeks Is Associated With Small for Gestational Age at Birth

Detecting SGA (small for gestational age) during pregnancy improves the fetal and neonatal prognosis. To date, there is no valid antenatal biomarker of SGA used in clinical practice. Maternal circulating DLK1 (delta-like non-canonical notch ligand 1) levels have been shown to be significantly lower in pregnant women at 36 weeks of gestation (WG) who delivered a SGA newborn than in controls. Data in the literature are contradictory on the association between maternal circulating DLK1 levels and placental vascular dysfunction. The objective was to determine if maternal DLK1 levels in the second trimester of pregnancy are predictive of SGA, and to assess whether the measurement of DLK1 levels in maternal blood could be a means to distinguish SGA with placental vascular dysfunction from that due to other causes. We conducted a nested cased-control study within the EDEN mother-child cohort. 193 SGA (birth weight < 10^th percentile) and 370 mother-child control (birth weight between the 25^th and 75^th percentile) matched pairs were identified in the EDEN cohort. Maternal circulating DLK1 levels at 26 WG were significantly lower for children born SGA than for controls (27.7 ± 8.7 ng/mL vs 30.4 ± 10.6 ng/mL, p = 0.001). Maternal blood DLK1 levels in the first quartile (DLK1 < 22.85 ng/mL) were associated with an odds ratio for SGA of 1.98 [1.15 - 3.37]. DLK1 was less predictive of SGA than ultrasound, with an area under the curve of 0.578. Maternal circulating DLK1 levels were not significantly different in cases of SGA with signs of placental vascular dysfunction (n = 63, 27.1 ± 9.2 ng/mL) than in those without placental dysfunction (n = 129, 28.0 ± 8.5 ng/mL, p = 0.53). The level of circulating DLK1 is reduced in the second trimester of pregnancy in cases of SGA at birth, independently of signs of placental vascular dysfunction. However, DLK1 alone cannot predict the risk of SGA.

Fertility preservation in young men with Klinefelter syndrome: A systematic review

BACKGROUND

Klinefelter syndrome (KS) is the most common cause of genetic male infertility, as most patients present azoospermia. In the testis, a massive decrease in the number of germinal cells is observed and this can begin early in childhood. Thus, it is possible to collect spermatozoa after sperm collection or thanks to testicular sperm extraction (TESE), but the chances finding spermatozoa are decreasing with the age. Sperm collection or TESE should be performed as early as possible. When KS is diagnosed during childhood or teens, fertility preservation could be beneficial. The minimal age for proposing fertility preservation remains controversial and there is no current recommendation about fertility preservation in young men with KS.

DESIGN

In this context, we have conducted a systematic review of the results of fertility preservation in young patients with KS to discuss the optimal age range for offering fertility preservation, including or not a TESE.

RESULTS

Six articles were included in the systematic review, with patients between 13 and 24 years-old. Except for one, all young men agreed for sperm collection following masturbation. Azoospermia was diagnosed in all patients presenting homogenous KS. One study reported the presence of spermatozoa in the ejaculate of a young man with mosaic KS. Fifty-eight young man for whom ejaculated sperm collection was unsuccessful have benefited from TESE. Testicular spermatozoa were found and frozen in 27 patients out of the 58 (46.5%). The chances of freezing viable testicular sperm between 14 and 23 years of age do not appear to depend on age.

CONCLUSION

Fertility preservation should be proposed in young men, but the optimal age for proposing the first sperm collection could be adapted according to the medical context and the psychological maturity of the young man.

Contribution of functionally assessed GHRHR mutations to idiopathic isolated growth hormone deficiency in patients without GH1 mutations

Isolated growth hormone deficiency (IGHD) is a rare condition mainly caused by mutations in GH1. The aim of this study was to assess the contribution of GHRHR mutations to IGHD in an unusually large group of patients. All GHRHR coding exons and flanking intronic regions were sequenced in 312 unrelated patients with nonsyndromic IGHD. Functional consequences of all newly identified missense variants were assessed in vitro (i.e., study of the expression of recombinant GHRHRs and their ability to activate the cyclic adenosine monophosphate (cAMP) signaling pathway). Genotype-phenotype correlation analyses were performed according to the nature of the identified mutation. We identified 20 different disease-causing GHRHR mutations (truncating and missense loss-of-function mutations), among which 15 are novel, in 24 unrelated patients. Of note, about half (13/24) of those patients represent sporadic cases. The clinical phenotype of patients with at least one missense GHRHR mutation was found to be indistinguishable from that of patients with bi-allelic truncating mutations. This study, which unveils disease-causing GHRHR mutations in 8% (24/312) of IGHD cases, identifies GHRHR as the second IGHD gene most frequently involved after GH1. The finding that 8% of IGHD cases without GH1 mutations are explained by GHRHR molecular defects (including missense mutations), together with the high proportion of sporadic cases among those patients, has important implications for genetic counseling.

Placental Pathology in Beckwith-Wiedemann Syndrome According to Genotype/Epigenotype Subgroups

OBJECTIVES

To evaluate the frequency of placental pathological lesions in Beckwith-Wiedemann syndrome (BWS), an overgrowth disorder that exhibits etiologic molecular heterogeneity and variable phenotypic expression.

MATERIALS AND METHODS

The study included 60 BWS patients with a proven molecular diagnosis and a placental pathological examination. Placentomegaly, placental mesenchymal dysplasia (PMD), chorangioma/chorangiomatosis, and extravillous trophoblastic (EVT) cytomegaly were evaluated and their frequencies in the different molecular subgroups were compared. Immunohistochemistry and fluorescent in situ hybridization (FISH) were performed on EVT cytomegaly.

RESULTS

Placentomegaly was found in 70.9% of cases, PMD in 21.7%, chorangioma/chorangiomatosis in 23.3%, and EVT cytomegaly in 21.7%; there was no significant intergroup difference. EVT cytomegaly showed loss of p57 expression, increased Ki67 proliferating index, and polyploidy on FISH analysis.

CONCLUSIONS

There was no genotype/epigenotype-phenotype correlation concerning placental lesions in BWS. Diffuse EVT cytomegaly with polyploidy may represent a placental finding suggestive of BWS.

Study of the Factors Leading to Fetal and Neonatal Dysthyroidism in Children of Patients With Graves Disease

CONTEXT

Neonatal hyperthyroidism was first described in 1912 and in 1964 was shown to be linked to transplacental passage of maternal antibodies. Few multicenter studies have described the perinatal factors leading to fetal and neonatal dysthyroidism.

OBJECTIVE

To show how fetal dysthyroidism (FD) and neonatal dysthyroidism (ND) can be predicted from perinatal variables, in particular, the levels of anti-thyrotropin receptor antibodies (TRAbs) circulating in the mother and child.

DESIGN AND PATIENTS

This was a retrospective multicenter study of data from the medical records of all patients monitored for pregnancy from 2007 to 2014.

SETTING

Among 280,000 births, the medical records of 2288 women with thyroid dysfunction were selected and screened, and 417 women with Graves disease and positive for TRAbs during pregnancy were included.

RESULTS

Using the maternal TRAb levels, the cutoff value of 2.5 IU/L best predicted for FD, with a sensitivity of 100% and specificity of 64%. Using the newborn TRAb levels, the cutoff value of 6.8 IU/L best predicted for ND, with a sensitivity of 100% and a specificity of 94%. In our study, 65% of women with a history of Graves disease did not receive antithyroid drugs during pregnancy but still had infants at risk of ND.

CONCLUSIONS

In pregnant women with TRAb levels ≥2.5 IU/L, fetal ultrasound monitoring is essential until delivery. All newborns with TRAb levels ≥6.8 IU/L should be examined by a pediatrician with special attention for thyroid dysfunction and treated, if necessary.

Nomenclature and definition in asymmetric regional body overgrowth

We designate a novel term "isolated lateralized overgrowth" (ILO) for the findings previously described as "isolated hemihypertrophy" and "isolated hemihyperplasia." ILO is defined as lateralized overgrowth in the absence of a recognized pattern of malformations, dysplasia, or morphologic variants. ILO is likely genetically heterogeneous. Further study is required to determine more of the underlying genetic etiologies and potential associations with currently unrecognized patterns of malformation.

Hypercortisolism due to a Pituitary Adenoma Associated with Beckwith-Wiedemann Syndrome

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome with an increased risk of cancer. Most BWS patients show a molecular defect in the 11p15 region that contains imprinted genes. BWS has been associated with malignant neoplasms during infancy. Descriptions of benign tumors, especially in adult patients, are rarer.

METHODS/RESULTS

We report the case of a BWS patient with pituitary adenoma caused by loss of methylation (LOM) at ICR2 (locus CDKN1C/KCNQ1OT1). The patient was referred to an endocrinology unit for suspicion of Cushing's disease due to a history of macroglossia and hemihyperplasia. Biological tests led to the diagnosis of ACTH-dependent hypercortisolism. MRI showed a microadenoma of the pituitary gland, confirming the diagnosis of Cushing's disease. DNA methylation analysis revealed LOM at ICR2 that was in a mosaic state in the patient's leukocytes, but was present in nearly all cells of the pituitary adenoma. The epigenetic defect was associated with a somatic USP8 mutation in the adenoma.

CONCLUSION

Pituitary adenoma rarely occurs in patients with BWS. However, BWS should be considered in cases of pituitary adenoma with minor and/or major signs of BWS. The association between ICR2 LOM and USP8 mutation in the adenoma is questionable. © 2016 S. Karger AG, Basel.

Contribution of LHX4 Mutations to Pituitary Deficits in a Cohort of 417 Unrelated Patients

CONTEXT

LHX4 encodes a LIM-homeodomain transcription factor that is implicated in early pituitary development. In humans, only 13 heterozygous LHX4 mutations have been associated with congenital hypopituitarism.

OBJECTIVE

The aims of this study were to evaluate the prevalence of LHX4 mutations in patients with hypopituitarism, to define the associated phenotypes, and to characterize the functional impact of the identified variants and the respective role of the 2 LIM domains of LHX4.

DESIGN AND PATIENTS

We screened 417 unrelated patients with isolated growth hormone deficiency or combined pituitary hormone deficiency associated with ectopic posterior pituitary and/or sella turcica anomalies for LHX4 mutations (Sanger sequencing). In vitro studies were performed to assess the functional consequences of the identified variants.

RESULTS

We identified 7 heterozygous variations, including p.(Tyr131*), p.(Arg48Thrfs*104), c.606+1G>T, p.Arg65Val, p.Thr163Pro, p.Arg221Gln, and p.Arg235Gln), that were associated with variable expressivity; 5 of the 7 were also associated with incomplete penetrance. The p.(Tyr131*), p.(Arg48Thrfs*104), p.Ala65Val, p.Thr163Pro, and p.Arg221Gln LHX4 variants are unable to transactivate the POU1F1 and GH promoters. As suggested by transactivation, subcellular localization, and protein-protein interaction studies, p.Arg235Gln is probably a rare polymorphism. Coimmunoprecipitation studies identified LHX3 as a potential protein partner of LHX4. As revealed by functional studies of LIM-defective recombinant LHX4 proteins, the LIM1 and LIM2 domains are not redundant.

CONCLUSION

This study, performed in the largest cohort of patients screened so far for LHX4 mutations, describes 6 disease-causing mutations that are responsible for congenital hypopituitarism. LHX4 mutations were found to be associated with variable expressivity, and most of them with incomplete penetrance; their contribution to pituitary deficits that are associated with an ectopic posterior pituitary and/or a sella turcica defect is ∼1.4% in the 417 probands tested.

11p15 ICR1 Partial Deletions Associated with IGF2/H19 DMR Hypomethylation and Silver-Russell Syndrome

The 11p15 region harbors the IGF2/H19 imprinted domain, implicated in fetal and postnatal growth. Silver-Russell syndrome (SRS) is characterized by fetal and postnatal growth failure, and is caused principally by hypomethylation of the 11p15 imprinting control region 1 (ICR1). However, the mechanisms leading to ICR1 hypomethylation remain unknown. Maternally inherited genetic defects affecting the ICR1 domain have been associated with ICR1 hypermethylation and Beckwith-Wiedemann syndrome (an overgrowth syndrome, the clinical and molecular mirror of SRS), and paternal deletions of IGF2 enhancers have been detected in four SRS patients. However, no paternal deletions of ICR1 have ever been associated with hypomethylation of the IGF2/H19 domain in SRS. We screened for new genetic defects within the ICR1 in a cohort of 234 SRS patients with hypomethylated IGF2/H19 domain. We report deletions close to the boundaries of ICR1 on the paternal allele in one familial and two sporadic cases of SRS with ICR1 hypomethylation. These deletions are associated with hypomethylation of the remaining CBS, and decreased IGF2 expression. These results suggest that these regions are most likely required to maintain methylation after fertilization. We estimate these anomalies to occur in about 1% of SRS cases with ICR1 hypomethylation.

Is Nephron Sparing Surgery Justified in Wilms Tumor With Beckwith-Wiedemann Syndrome or Isolated Hemihypertrophy?

BACKGROUND

Patients with Beckwith-Wiedemann syndrome (BWS) or isolated hemihypertrophy (HH) treated for a Wilms tumor (WT) carry an increased risk of developing metachronous lesion. There are no guidelines on precise indications for nephron sparing surgery (NSS) in unilateral WT (UWT). The objective of this retrospective study was to delineate the indications of NSS in patients with BWS/HH treated for WT and to evaluate their outcome.

PROCEDURE

All cases of BWS/HH treated for a WT according to SIOP protocols from 1980 to 2013 were reviewed. Patients were divided into two groups (G): isolated UWT (G1) and bilateral lesions (G2) with two subgroups: bilateral tumors suspected of malignancy (G2a), and unilateral tumor suspected of malignancy with contralateral nephroblastomatosis (G2b).

RESULTS

Forty-six patients were included (34 G1, three G2a, and nine G2b). Nine NSS and 25 total nephrectomies (TN) were performed in G1, two bilateral NSS and one NSS with contralateral TN in G2a, and eight NSS and one TN in G2b. The 3-year event-free survival was 92.3% (95% CI [77.9-97.5%]). One death occurred after a local relapse following a TN for a stage III stromal WT (G1) and another after a combined local and distant relapse following a NSS for a stage I diffuse anaplastic WT (G2b). There were two metachronous WT (4%), 3 years after a TN (G1) and 12 years after a NSS (G2b).

CONCLUSIONS

NSS is recommended in bilateral WT and may be an option in selected UWT patients with BWS/HH because it was not associated with an increased risk of local relapse.

Mutations of the Imprinted CDKN1C Gene as a Cause of the Overgrowth Beckwith-Wiedemann Syndrome: Clinical Spectrum and Functional Characterization

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder associating macroglossia, abdominal wall defects, visceromegaly, and a high risk of childhood tumor. Molecular anomalies are mostly epigenetic; however, mutations of CDKN1C are implicated in 8% of cases, including both sporadic and familial forms. We aimed to describe the phenotype of BWS patients with CDKN1C mutations and develop a functional test for CDKN1C mutations. For each propositus, we sequenced the three exons and intron-exon boundaries of CDKN1C in patients presenting a BWS phenotype, including abdominal wall defects, without 11p15 methylation defects. We developed a functional test based on flow cytometry. We identified 37 mutations in 38 pedigrees (50 patients and seven fetuses). Analysis of parental samples when available showed that all mutations tested but one was inherited from the mother. The four missense mutations led to a less severe phenotype (lower frequency of exomphalos) than the other 33 mutations. The following four tumors occurred: one neuroblastoma, one ganglioneuroblastoma, one melanoma, and one acute lymphoid leukemia. Cases of BWS caused by CDKN1C mutations are not rare. CDKN1C sequencing should be performed for BWS patients presenting with abdominal wall defects or cleft palate without 11p15 methylation defects or body asymmetry, or in familial cases of BWS.

Beckwith-Wiedemann syndrome: growth pattern and tumor risk according to molecular mechanism, and guidelines for tumor surveillance

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome associated with an increased risk of pediatric tumors. The underlying molecular abnormalities may be genetic (CDKN1C mutations or 11p15 paternal uniparental isodisomy, pUPD) or epigenetic (imprinting center region 1, ICR1, gain of methylation, ICR1 GOM, or ICR2 loss of methylation, ICR2 LOM).

AIM

We aimed to describe a cohort of 407 BWS patients with molecular defects of the 11p15 domain followed prospectively after molecular diagnosis.

RESULTS

Birth weight and length were significantly higher in patients with ICR1 GOM than in the other groups. ICR2 LOM and CDKN1C mutations were associated with a higher prevalence of exomphalos. Mean adult height (regardless of molecular subtype, n = 35) was 1.8 ± 1.2 SDS, with 18 patients having a final height above +2 SDS. The prevalence of tumors was 8.6% in the whole population; 28.6 and 17.3% of the patients with ICR1 GOM (all Wilms tumors) and 11p15 pUPD, respectively, developed a tumor during infancy. Conversely, the prevalence of tumors in patients with ICR2 LOM and CDKN1C mutations were 3.1 and 8.8%, respectively, with no Wilms tumors.

CONCLUSION

Based on these results for a large cohort, we formulated guidelines for the follow-up of these patients according to the molecular subtype of BWS.

CDKN1C mutation affecting the PCNA-binding domain as a cause of familial Russell Silver syndrome

BACKGROUND

Russell Silver syndrome (RSS) leads to prenatal and postnatal growth retardation. About 55% of RSS patients present a loss-of-methylation of the paternal ICR1 domain on chromosome 11p15. CDKN1C is a cell proliferation inhibitor encoded by an imprinted gene in the 11p15 ICR2 domain. CDKN1C mutations lead to Beckwith Wiedemann syndrome (BWS, overgrowth syndrome) and in IMAGe syndrome which associates growth retardation and adrenal insufficiency. We searched for CDKN1C mutations in a cohort of clinically diagnosed RSS patients with no molecular anomaly.

METHOD

The coding sequence and intron-exon boundaries of CDKN1C were analysed in 97 RSS patients. The impact of CDKN1C variants on the cell cycle in vitro were determined by flow cytometry. Stability of CDKN1C was studied by western immunoblotting after inhibition of translation with cycloheximide.

RESULTS

We identified the novel c.836G>[G;T] (p.Arg279Leu) mutation in a familial case of intrauterine growth retardation (IUGR) with RSS phenotype and no evidence of IMAGe. All the RSS patients inherited this mutation from their mothers (consistent with monoallelic expression from the maternal allele of the gene). A mutation of this amino acid (p.Arg279Pro) has been reported in cases of IMAGe. Functional analysis showed that Arg279Leu (RSS) did not affect the cell cycle, whereas the Arg279Pro mutation (IMAGe) led to a gain of function. Arg279Leu (RSS) led to an increased stability which could explain an increased activity of CDKN1C.

CONCLUSIONS

CDKN1C mutations cause dominant maternally transmitted RSS, completing the molecular mirror with BWS. CDKN1C should be investigated in cases with family history of RSS.