Susanne Kjaergaard

Serum Levels of Anti-Müllerian Hormone as a Marker of Ovarian Function in 926 Healthy Females from Birth to Adulthood and in 172 Turner Syndrome Patients

CONTEXT In adult women, anti-Müllerian hormone (AMH) is related to the ovarian follicle pool. Little is known about AMH in girls. OBJECTIVE The objective of the study was to provide a reference range for AMH in girls and adolescents and to evaluate AMH as a marker of ovarian function. SETTING The study was conducted at a tertiary referral center for pediatric endocrinology. MAIN OUTCOME MEASURES We measured AMH in 926 healthy females (longitudinal values during infancy) as well as in 172 Turner syndrome (TS) patients according to age, karyotype (A: 45,X; B: miscellaneous karyotypes; C: 45,X/46,XX), and ovarian function (1: absent puberty; 2: cessation of ovarian function; 3: ongoing ovarian function). RESULTS AMH was undetectable in 54% (38 of 71) of cord blood samples (<2; <2-15 pmol/liter) (median; 2.5th to 97.5th percentile) and increased in all (37 of 37) infants from birth to 3 months (15; 4.5-29.5 pmol/liter). From 8 to 25 yr, AMH levels were stable (19.9; 4.7-60.1 pmol/liter), with the lower level of the reference range clearly above the detection limit. AMH levels were associated with TS-karyotype groups (median A vs. B: <2 vs. 3 pmol/liter, P = 0.044; B vs. C: 3 vs. 16 pmol/liter, P < 0.001) as well as with ovarian function (absent puberty vs. cessation of ovarian function: <2 vs. 6 pmol/liter, P = 0.004; cessation of ovarian function vs. ongoing ovarian function: 6 vs. 14 pmol/liter, P = 0.001). As a screening test of premature ovarian failure in TS, the sensitivity and specificity of AMH less than 8 pmol/liter was 96 and 86%, respectively. CONCLUSION AMH seems to be a promising marker of ovarian function in healthy girls and TS patients.

De novo nonsense mutations in ASXL1 cause Bohring-Opitz syndrome

Bohring-Opitz syndrome is characterized by severe intellectual disability, distinctive facial features and multiple congenital malformations. We sequenced the exomes of three individuals with Bohring-Opitz syndrome and in each identified heterozygous de novo nonsense mutations in ASXL1, which is required for maintenance of both activation and silencing of Hox genes. In total, 7 out of 13 subjects with a Bohring-Opitz phenotype had de novo ASXL1 mutations, suggesting that the syndrome is genetically heterogeneous.

The immune response to chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients is predominantly of the Th2 type

Most cystic fibrosis (CF) patients with chronic Pseudomonas aeruginosa lung infection have a persistent acute type lung inflammation dominated by polymorphonuclear neutrophils (PMN) and a pronounced antibody response against P. aeruginosa. We speculated whether this immune response in CF is of the Th2 type and whether a change to a Th1 type immune response could improve the prognosis. Therefore, we studied 14 CF patients with (CF +P) and 14 CF patients without (CF –P) chronic P. aeruginosa lung infection. The specific production of interferon‐gamma (IFN‐γ) and interleukin‐4 (IL‐4) by peripheral blood mononuclear cells was determined. Cells from CF +P patients had lower IFN‐γ (p<0.05) and higher IL‐4 (p<0.005) production as compared to cells from CF ‐P patients. Furthermore, a positive correlation between IFN‐γ production and lung function was found (FVC: Rho=0.637; p<0.03; FEV1: Rho=0.524; p<0.07). We conclude that a Th2 type immune response is most frequent in CF patients with chronic P. aeruginosa lung infection, and the patients with a Th1‐dominated immune response had the best lung function. The clinical implication is that a change to a Th1 type immune response might improve the prognosis in these patients.

Mutations in PMM2 that cause congenital disorders of glycosylation, type Ia (CDG-Ia)

The PMM2 gene, which is defective in CDG‐Ia, was cloned three years ago [Matthijs et al., 1997b]. Several publications list PMM2 mutations [Matthijs et al., 1997b, 1998; Kjaergaard et al., 1998, 1999; Bjursell et al., 1998, 2000; Imtiaz et al., 2000] and a few mutations have appeared in case reports or abstracts [Crosby et al., 1999; Kondo et al., 1999; Krasnewich et al., 1999; Mizugishi et al., 1999; Vuillaumier‐Barrot et al., 1999, 2000b]. However, the number of molecularly characterized cases is steadily increasing and many new mutations may never make it to the literature. Therefore, we decided to collate data from six research and diagnostic laboratories that have committed themselves to a systematic search for PMM2 mutations. In total we list 58 different mutations found in 249 patients from 23 countries. We have also collected demographic data and registered the number of deceased patients. The documentation of the genotype–phenotype correlation is certainly valuable, but is out of the scope of this molecular update. The list of mutations will also be available online (URL: http://www.kuleuven.ac.be/med/cdg) and investigators are invited to submit new data to this PMM2 mutation database. Hum Mutat 16:386–394, 2000.

Increased Number of Sex Chromosomes Affects Height in a Nonlinear Fashion: A Study of 305 Patients With Sex Chromosome Aneuploidy

Tall stature and eunuchoid body proportions characterize patients with 47,XXY Klinefelter syndrome, whereas patients with 45,X Turner syndrome are characterized by impaired growth. Growth is relatively well characterized in these two syndromes, while few studies describe the growth of patients with higher grade sex chromosome aneuploidies. It has been proposed that tall stature in sex chromosome aneuploidy is related to an overexpression of SHOX, although the copy number of SHOX has not been evaluated in previous studies. Our aims were therefore: (1) to assess stature in 305 patients with sex chromosome aneuploidy and (2) to determine the number of SHOX copies in a subgroup of these patients (n = 255) these patients and 74 healthy controls. Median height standard deviation scores in 46,XX males (n = 6) were −1.2 (−2.8 to 0.3), +0.9 (−2.2 to +4.6) in 47,XXY (n = 129), +1.3 (−1.8 to +4.9) in 47,XYY (n = 44), +1.1 (−1.9 to +3.4) in 48,XXYY (n = 45), +1.8 (−2.0 to +3.2) in 48,XXXY (n = 9), and −1.8 (−4.2 to −0.1) in 49,XXXXY (n = 10). Median height standard deviation scores in patients with 45,X (n = 6) were −2.6 (−4.1 to −1.6), +0.7 (−0.9 to +3.2) in 47,XXX (n = 40), −0.6 (−1.9 to +2.1) in 48,XXXX (n = 13), and −1.0 (−3.5 to −0.8) in 49,XXXXX (n = 3). Height increased with an increasing number of extra X or Y chromosomes, except in males with five, and in females with four or five sex chromosomes, consistent with a nonlinear effect on height.

Corpus callosum abnormalities, intellectual disability, speech impairment, and autism in patients with haploinsufficiency of ARID1B

Halgren C, Kjaergaard S, Bak M, Hansen C, El‐Schich Z, Anderson CM, Henriksen KF, Hjalgrim H, Kirchhoff M, Bijlsma EK, Nielsen M, den Hollander NS, Ruivenkamp CAL, Isidor B, Le Caignec C, Zannolli R, Mucciolo M, Renieri A, Mari F, Anderlid B‐M, Andrieux J, Dieux A, Tommerup N, Bache I. Corpus callosum abnormalities, intellectual disability, speech impairment, and autism in patients with haploinsufficiency of ARID1B.

45,X/46,XY mosaicism: phenotypic characteristics, growth, and reproductive function--a retrospective longitudinal study.

CONTEXT Most previous studies of 45,X/46,XY mosaicism are case reports or have described single aspects of the disease. OBJECTIVE The objective was to provide longitudinal data of patients with 45,X/46,XY mosaicism. DESIGN This was a retrospective, longitudinal study conducted from June 1990 to January 2012. SETTING The study took place at a tertiary pediatric and andrological referral center. PATIENTS OR OTHER PARTICIPANTS Twenty-five patients (18 boys, seven girls) with 45,X/46,XY mosaicism and its variants were included and were compared to healthy controls. INTERVENTION(S) No interventions were included in the study. MAIN OUTCOME MEASURE(S) Phenotypes were scored using external masculinization scores. Serum LH, FSH, testosterone, estradiol, and inhibin B levels were reported in male patients. IGF-I levels and height were reported in all patients. Available biopsies/gonadectomies were histologically examined. RESULTS Fourteen of 18 males had external masculinization scores consistent with normal virilization. Ten of 11 male patients experienced spontaneous puberty. Median height sd score was -2.0 (range, -3 to 0.3) for males and -2.2 (range, -2.5 to -1.4) for females, both considerably below genetic potential. Median 1-yr height gain after GH treatment in seven patients was 0.5 sd (0.1 to 1.2). All tissue samples from 15 patients (eight males, seven females) revealed abnormal gonadal histology. Four patients had carcinoma in situ (CIS); two had tissue samples available from early childhood, one showing CIS. CONCLUSIONS Gonadal function in most 45,X/46,XY males, even those with genital ambiguity, seems sufficient for spontaneous puberty. Short stature and 45,X/46,XY mosaicism seem associated, but patients appear to benefit from GH treatment. Histology from two patients with biopsies from early childhood indicates that CIS originates before puberty.

De Novo Mutations in the Genome Organizer CTCF Cause Intellectual Disability

An increasing number of genes involved in chromatin structure and epigenetic regulation has been implicated in a variety of developmental disorders, often including intellectual disability. By trio exome sequencing and subsequent mutational screening we now identified two de novo frameshift mutations and one de novo missense mutation in CTCF in individuals with intellectual disability, microcephaly, and growth retardation. Furthermore, an individual with a larger deletion including CTCF was identified. CTCF (CCCTC-binding factor) is one of the most important chromatin organizers in vertebrates and is involved in various chromatin regulation processes such as higher order of chromatin organization, enhancer function, and maintenance of three-dimensional chromatin structure. Transcriptome analyses in all three individuals with point mutations revealed deregulation of genes involved in signal transduction and emphasized the role of CTCF in enhancer-driven expression of genes. Our findings indicate that haploinsufficiency of CTCF affects genomic interaction of enhancers and their regulated gene promoters that drive developmental processes and cognition.

FSH, LH, inhibin B and estradiol levels in Turner syndrome depend on age and karyotype: longitudinal study of 70 Turner girls with or without spontaneous puberty

BACKGROUND Ovarian function in Turner syndrome (TS) patients depends on the specific karyotype. This retrospective clinical study evaluates the pituitary-gonadal axis during infancy, childhood and adolescence in TS patients according to karyotype and ovarian function. METHODS A cohort of 70 TS patients (0-16 years) followed at a tertiary referral centre for paediatric endocrinology were included. Longitudinal measurements of reproductive hormones (FSH, LH, inhibin B and estradiol) prior to hormonal replacement treatment in 66 patients related to karyotype (A, 45,X; or B, miscellaneous karyotypes) and ovarian function (spontaneous puberty or absent spontaneous puberty) were compared with an age-matched reference range of 2406 healthy Danish females. RESULTS The prevalence of spontaneous puberty was 6% for 45,X and 54% for miscellaneous karyotypes, P = 0.001. In all TS patients, gonadotrophins were higher during infancy and at expected puberty compared with levels at mid-childhood, where 21/25 and 23/27 had FSH and LH levels, respectively, within the reference range. In patients with absent spontaneous puberty, 10/12 had FSH in the reference range during the mid-childhood nadir. 45,X-TS patients had undetectable inhibin B at 0-16 years. Ovarian failure was predicted in 20/20 patients with exclusively undetectable inhibin B, while 9/10 with detectable inhibin B entered puberty spontaneously. Estradiol levels were elevated from 4 to 8 years. CONCLUSIONS Ovarian function in TS patients is associated with the specific karyotype, and multiple undetectable inhibin B values during mid-childhood may predict absence of spontaneous puberty, although the specificity of the test is low. The biphasic age pattern of gonadotrophins was preserved in all patients, and spontaneous gonadotrophins are not useful as a diagnostic marker for TS in girls aged 6-10 years.

Molecular genetic basis and prevalence of glycogen storage disease type IIIA in the Faroe Islands.

Glycogen storage disease type IIIA (GSD IIIA) is caused by mutations of the amyloglucosidase gene (AGL). For most populations, none of the AGL mutations described to date is particularly frequent. In this paper, we report that six children with GSD IIIA from the Faroe Islands were found to be homozygous for the novel nonsense mutation c.1222C>T (R408X) of the AGL gene. This mutation is easily detected by restriction enzyme digest with NsiI after mismatch PCR. Investigating five intragenic polymorphisms, we could show that this mutation was always associated with the same haplotype. The c.1222C>T mutation could be detected on two chromosomes of another 50 unselected GSD IIIA patients of other European or North American origin which means that this mutation plays a minor role worldwide. From the fact that we are currently aware of a total of 14 GSD IIIA cases in the Faroese population of 45 000, the observed prevalence is 1 : 3100. While the novel AGL mutation c.1222C>T was not detectable among 198 German newborns, nine out of 272 children from the Faroese neonatal screening program were found to be heterozygous for this mutation. Thus, the calculated prevalence is 1 : 3600 (95% CI 1:700–1:6400). We conclude that due to a founder effect, the Faroe Islands have the highest prevalence of GSD IIIA world-wide. The detection of the molecular defect has facilitated the diagnosis and has offered the opportunity for prenatal diagnosis in this patient group.