Chromosomal anomalies in patients with short stature

White matter microstructure and functional connectivity in the brains of infants with Turner syndrome

Turner syndrome, caused by complete or partial loss of an X-chromosome, is often accompanied by specific cognitive challenges. Magnetic resonance imaging studies of adults and children with Turner syndrome suggest these deficits reflect differences in anatomical and functional connectivity. However, no imaging studies have explored connectivity in infants with Turner syndrome. Consequently, it is unclear when in development connectivity differences emerge. To address this gap, we compared functional connectivity and white matter microstructure of 1-year-old infants with Turner syndrome to typically developing 1-year-old boys and girls. We examined functional connectivity between the right precentral gyrus and five regions that show reduced volume in 1-year old infants with Turner syndrome compared to controls and found no differences. However, exploratory analyses suggested infants with Turner syndrome have altered connectivity between right supramarginal gyrus and left insula and right putamen. To assess anatomical connectivity, we examined diffusivity indices along the superior longitudinal fasciculus and found no differences. However, an exploratory analysis of 46 additional white matter tracts revealed significant group differences in nine tracts. Results suggest that the first year of life is a window in which interventions might prevent connectivity differences observed at later ages, and by extension, some of the cognitive challenges associated with Turner syndrome.

Internipple Distance and Internipple Index in Prepubertal Turkish Girls

OBJECTIVE

To determine internipple distance and internipple index in prepubertal Turkish girls.

METHODS

The internipple distance and chest circumference of 667 healthy prepubertal Turkish girls aged 6 to 11 years were measured in a school screening program in Düzce. Measurements were performed at the end of expiration with a standard non-stretch tape measure graduated in millimeters with the arms hanging in a relaxed position on the sides of the body. The internipple distance was measured between the centers of both nipples, and chest circumference was measured across the internipple line. The internipple index was calculated by dividing the internipple distance (cm) x100 by the chest circumference (cm). Age specific internipple index reference curves were constructed and smoothed with the Lambda-Mu-Sigma method. Mean and standard deviations of internipple distance and internipple index were calculated according to decimal ages.

RESULTS

Age was found to be positively correlated with internipple distance and chest circumference, while it was negatively correlated with internipple index. The reference values of internipple index, including 3^rd, 10^th, 25^th, 50^th, 75^th, 90^th, and 97^th percentiles, and standard deviations were calculated for prepubertal girls.

CONCLUSION

The reference ranges provided by this study might be helpful for the evaluation of syndromic cases by serving as normative data for internipple index in prepubertal girls aged 6-11 years in Turkey although ethnic differences may affect applicability to other countries.

Towards a Rational and Efficient Diagnostic Approach in Children Referred for Growth Failure to the General Paediatrician

Based on a recent Dutch national guideline, we propose a structured stepwise diagnostic approach for children with growth failure (short stature and/or growth faltering), aiming at high sensitivity for pathologic causes at acceptable specificity. The first step is a detailed clinical assessment, aiming at obtaining relevant clinical clues from the medical history (including family history), physical examination (emphasising head circumference, body proportions and dysmorphic features) and assessment of the growth curve. The second step consists of screening: a radiograph of the hand and wrist (for bone age and assessment of anatomical abnormalities suggestive for a skeletal dysplasia) and laboratory tests aiming at detecting disorders that can present as isolated short stature (anaemia, growth hormone deficiency, hypothyroidism, coeliac disease, renal failure, metabolic bone diseases, renal tubular acidosis, inflammatory bowel disease, Turner syndrome [TS]). We advise molecular array analysis rather than conventional karyotyping for short girls because this detects not only TS but also copy number variants and uniparental isodisomy, increasing diagnostic yield at a lower cost. Third, in case of diagnostic clues for primary growth disorders, further specific testing for candidate genes or a hypothesis-free approach is indicated; suspicion of a secondary growth disorder warrants adequate further targeted testing.

FSH may be a useful tool to allow early diagnosis of Turner syndrome

BACKGROUND

Ultrasensitive assays to measure pre-pubertal gonadotropins levels could help identify patients with Turner syndrome (TS) in mid-childhood, but studies in this field are scarce. The aim of this study was to analyze gonadotropins levels in girls with TS throughout childhood.

METHODS

Retrospective longitudinal study conducted with 15 girls with TS diagnosed with < 5 years whose FSH and LH measures were available since then. Hormones were evaluated in newborn/mini-puberty (< 0.5 years), early childhood (0.5-5 years), mid-childhood (5-10 years) and late childhood/adolescence (> 10 years). In newborn/mini-puberty and late childhood/adolescence pre-pubertal or pubertal gonadotropins were considered normal; in early childhood and mid-childhood concentrations above the pre-pubertal range were considered abnormal.

RESULTS

Abnormally high FSH alone was found in four of five patients in newborn/mini-puberty, 13 of 15 during early childhood and nine of 15 during mid-childhood. In the group of 12 patients in late childhood/adolescence, the three girls with spontaneous puberty had only normal levels; the remaining showed only post-menopausal concentrations. In mid-childhood one patient exhibited only pre-pubertal FSH. Conversely, most LH measurements in early and mid-childhood were normal.

CONCLUSION

Karyotyping of girls with short stature and high FSH levels would allow early diagnosis of Turner syndrome in a significant number of patients, particularly when resources for chromosome study of all girls with growth deficiency are limited.

MECHANISMS IN ENDOCRINOLOGY: Novel genetic causes of short stature

The fast technological development, particularly single nucleotide polymorphism array, array-comparative genomic hybridization, and whole exome sequencing, has led to the discovery of many novel genetic causes of growth failure. In this review we discuss a selection of these, according to a diagnostic classification centred on the epiphyseal growth plate. We successively discuss disorders in hormone signalling, paracrine factors, matrix molecules, intracellular pathways, and fundamental cellular processes, followed by chromosomal aberrations including copy number variants (CNVs) and imprinting disorders associated with short stature. Many novel causes of GH deficiency (GHD) as part of combined pituitary hormone deficiency have been uncovered. The most frequent genetic causes of isolated GHD are GH1 and GHRHR defects, but several novel causes have recently been found, such as GHSR, RNPC3, and IFT172 mutations. Besides well-defined causes of GH insensitivity (GHR, STAT5B, IGFALS, IGF1 defects), disorders of NFκB signalling, STAT3 and IGF2 have recently been discovered. Heterozygous IGF1R defects are a relatively frequent cause of prenatal and postnatal growth retardation. TRHA mutations cause a syndromic form of short stature with elevated T3/T4 ratio. Disorders of signalling of various paracrine factors (FGFs, BMPs, WNTs, PTHrP/IHH, and CNP/NPR2) or genetic defects affecting cartilage extracellular matrix usually cause disproportionate short stature. Heterozygous NPR2 or SHOX defects may be found in ∼3% of short children, and also rasopathies (e.g., Noonan syndrome) can be found in children without clear syndromic appearance. Numerous other syndromes associated with short stature are caused by genetic defects in fundamental cellular processes, chromosomal abnormalities, CNVs, and imprinting disorders.

Molecular cytogenetic characterization of a familial pericentric inversion 3 associated with short stature

Short stature refers to the height of an individual which is below expected. The causes are heterogenous and influenced by several genetic and environmental factors. Chromosomal abnormalities are a major cause of diseases and cytogenetic mapping is one of the powerful tools for the identification of novel disease genes. Here we report a three generation family with a heterozygous pericentric inversion of 46, XX, inv(3) (p24.1q26.1) associated with Short stature. Positional cloning strategy was used to physically map the breakpoint regions by Fluorescence in situ hybridization (FISH). Fine mapping was performed with Bacterial Artificial Chromosome (BAC) clones spanning the breakpoint regions. In order to further characterize the breakpoint regions extensive molecular mapping was carried out with the breakpoint spanning BACs which narrowed down the breakpoint region to 2.9 kb and 5.3 kb regions on p and q arm respectively. Although these breakpoints did not disrupt any validated genes, we had identified a novel putative gene in the vicinity of 3q26.1 breakpoint region by in silico analysis. Trying to find the presence of any transcripts of this putative gene we analyzed human total RNA by RT-PCR and identified transcripts containing three new exons confirming the existence of a so far unknown gene close to the 3q breakpoint.

Genetic evaluation of short stature

CONTEXT

Genetics plays a major role in determining an individual's height. Although there are many monogenic disorders that lead to perturbations in growth and result in short stature, there is still no consensus as to the role that genetic diagnostics should play in the evaluation of a child with short stature.

EVIDENCE ACQUISITION

A search of PubMed was performed, focusing on the genetic diagnosis of short stature as well as on specific diagnostic subgroups included in this article. Consensus guidelines were reviewed.

EVIDENCE SYNTHESIS

There are a multitude of rare genetic causes of severe short stature. There is no high-quality evidence to define the optimal approach to the genetic evaluation of short stature. We review genetic etiologies of a number of diagnostic subgroups and propose an algorithm for genetic testing based on these subgroups.

CONCLUSION

Advances in genomic technologies are revolutionizing the diagnostic approach to short stature. Endocrinologists must become facile with the use of genetic testing in order to identify the various monogenic disorders that present with short stature.

Analysis of short stature cases referred for genetic evaluation

OBJECTIVE

To retrospectively analyze the profile of patients who presented with chief complaint of short stature to Medical Genetics OPD of SGPGIMS, Lucknow, India.

METHODS

Medical Genetics OPD records were searched for cases presenting with short stature, from January 2008 through December 2010. Short stature was defined as height less than -2 SD from mean for the corresponding age and sex for the Indian population. The workup done for the cases was analyzed, following which they were placed in one of the etiological categories of short stature.

RESULTS

A total of 137 cases were analyzed. The number of female and male patients was 92 and 45 respectively. The evaluation done in majority of cases included anthropometry, calculation of mid-parental height, medical history, routine biochemistry and hematology, bone age assessment, thyroid function tests, antiendomysial antibody testing, karyotyping and other appropriate investigations as required. The percentages of cases in the various diagnostic categories were- skeletal dysplasia (32.1 %), turner syndrome (16.7 %), endocrine deficiencies (8 %), genetic syndromes (7.3 %), chronic diseases (5.8 %). Twenty one (15.3 %) cases grouped as idiopathic short stature consisted of 9 familial and 12 non-familial cases. Twenty (14.6 %) cases were found to be incompletely evaluated.

CONCLUSIONS

Skeletal dysplasias and turner syndrome accounted for majority of cases of short stature. Cause remains unidentified in 15.3 % cases and these idiopathic cases need further workup especially for the molecular defects in the pituitary GH-IGF1 axis. A detailed evaluation and good follow up of cases of short stature is required.

Chromosome abnormalities in Indonesian patients with short stature

Background

Short stature is associated with several disorders including wide variations of chromosomal disorders and single gene disorders. The objective of this report is to present the cytogenetic findings in Indonesian patients with short stature.

Methods

G-banding and interphase/metaphase FISH were performed on short stature patients with and without other clinical features who were referred by clinicians all over Indonesia to our laboratory during the year 2003–2009.

Results

The results of chromosomal analysis of ninety seven patients (mean age: 10.7 years old) were collected. The group of patients with other clinical features showed sex chromosome abnormalities in 45% (18/40) and autosomal abnormalities in 10% (4/40), whereas those with short stature only, 42.1% (24/57) had sex chromosome abnormalities and 1.75% (1/57) had autosomal abnormalities. The autosomal chromosomal abnormalities involved mostly subtelomeric regions. Results discrepancies between karyotype and FISH were found in 10 patients, including detection of low-level monosomy X mosaicism in 6 patients with normal karyotype, and detection of mosaic aneuploidy chromosome 18 in 1 patient with 45,XX,rob(13;14)(q10;q10).

Statistical analysis showed no significant association between the groups and the type of chromosomal abnormalities.

Conclusion

Chromosome abnormalities account for about 50% of the short stature patients. Wide variations of both sex and autosomal chromosomes abnormalities were detected in the study. Since three out of five patients had autosomal structural abnormalities involving the subtelomeric regions, thus in the future, subtelomeric FISH or even a more sensitive method such as genomic/SNP microarray is needed to confirm deletions of subtelomeric regions of chromosome 9, 11 and 18. Low-level mosaicism in normal karyotype patients indicates interphase FISH need to be routinely carried out in short stature patients as an adjunct to karyotyping.

Molecular Cytogenetic Characterization of a Non-Robertsonian Dicentric Chromosome 14;19 Identified in a Girl with Short Stature and Amenorrhea

We report a 16-year-old girl who presented with short stature and amenorrhea. Initially the cytogenetic analysis showed the presence of a mosaic non-Robertsonian dicentric chromosome involving chromosomes 14 and 19. Subsequent molecular cytogenetic analysis by fluorescence in situ hybridization (FISH) using whole chromosome paints, centromeric probes, as well as gene specific probes confirmed the dicentric nature of the derivative chromosome and indicated that the rearrangement involved the short arms of both of these chromosomes. Furthermore, we also determined that the chromosome 19p13.3 breakpoint occurred within the terminal 1 Mb region. This is the first report of a mosaic non-Robertsonian dicentric chromosome involving chromosomes 14 and 19 with the karyotype determined as 45,XX,dic(14;19)(p11.2;p13.3)[35]/46,XX[15], and we suggest that the chromosome rearrangement could be the cause of clinical phenotype.

Diagnóstico da Síndrome de Turner: a experiência do Instituto Estadual de Diabetes e Endocrinologia - Rio de Janeiro, de 1970 a 2008

OBJETIVOS: descrever a experiência no diagnóstico da Síndrome de Turner (ST), focalizando a distribuição dos cromossomos, a idade, os sinais e sintomas característicos, conforme as fases da vida (lactância, infância, adolescência e adulta). MÉTODOS: estudo descritivo com 178 pacientes, atendidos de 1970 até 2008. Para análise estatística das diferenças percentuais usou-se o Epi-Info-2000 e para as diferenças entre as médias de idades o teste t de Student e o ANOVA. RESULTADOS: os cariótipos encontrados foram: 79 com 45,X (35,4%), 36 com isocromossomo Xq (20,2%) e 63 com outros mosaicos (35,4%). A média de idade do diagnóstico foi de 12,6 anos, sendo menor naquelas com 45,X. Tiveram o diagnóstico feito na lactância 11,3% das pacientes, 25,3% na infância, 51,1% na adolescência e 12,4% na fase adulta. Daquelas diagnosticadas antes dos cinco anos de idade, 70,6% apresentaram 45,X. Os sinais que levaram à suspeita diagnóstica na lactância foram o pescoço alado e o linfedema congênito de pés/mãos associados às dismorfias típicas; na infância e adolescência foi a baixa estatura. Cubitus valgus foi encontrado em 72,5% das pacientes e orelhas anômalas em 65% das pacientes diagnosticadas com menos de um ano de idade. CONCLUSÃO: o diagnóstico da ST é desnecessariamente atrasado, levando-se em consideração que algumas características típicas podem já estar presentes desde o nascimento.

The diagnostic work up of growth failure in secondary health care; an evaluation of consensus guidelines

Background

As abnormal growth might be the first manifestation of undetected diseases, it is important to have accurate referral criteria and a proper diagnostic work-up. In the present paper we evaluate the diagnostic work-up in secondary health care according to existing consensus guidelines and study the frequency of underlying medical disorders.

Methods

Data on growth and additional diagnostic procedures were collected from medical records of new patients referred for short stature to the outpatient clinics of the general paediatric departments of two hospitals (Erasmus MC – Sophia Children's Hospital, Rotterdam and Spaarne Hospital, Haarlem) between January 1998 and December 2002. As the Dutch Consensus Guideline (DCG) is the only guideline addressing referral criteria as well as diagnostic work-up, the analyses were based on its seven auxological referral criteria to determine the characteristics of children who are incorrectly referred and the adequacy of workup of those who are referred.

Results

Twenty four percent of children older than 3 years were inappropriately referred (NCR). Of the correctly referred children 74–88% were short corrected for parental height, 40–61% had a height SDS <-2.5 and 21% showed height deflection (Δ HSDS < -0.25/yr or Δ HSDS < -1). In none of the children a complete detailed routine diagnostic work up was performed and in more than 30% no routine laboratory examination was done at all. Pathologic causes of short stature were found in 27 children (5%).

Conclusion

Existing guidelines for workup of children with suspected growth failure are poorly implemented. Although poorly implemented the DCG detects at least 5% pathologic causes of growth failure in children referred for short stature. New guidelines for referral are required with a better sensitivity and specificity, wherein distance to target height should get more attention. The general diagnostic work up for short stature should include testing for celiac disease in all children and for Turner syndrome in girls.

Idiopathic short stature: definition, epidemiology, and diagnostic evaluation

Idiopathic short stature is a condition in which the height of the individual is more than 2 SD below the corresponding mean height for a given age, sex and population, in whom no identifiable disorder is present. It can be subcategorized into familial and non-familial ISS, and according to pubertal delay. It should be differentiated from dysmorphic syndromes, skeletal dysplasias, short stature secondary to a small birth size (small for gestational age, SGA), and systemic and endocrine diseases. ISS is the diagnostic group that remains after excluding known conditions in short children.