Persistent Gynecomastia due to Short-term Low-dose Finasteride for Androgenetic Alopecia

We report a case of persistent gynecomastia in a healthy 20-year-old man after 1 month of low-dose finasteride. Finasteride was discontinued after 2 months, and gynecomastia was unchanged 5 months after drug withdrawal. The gynecomastia regressed but did not resolve after 6 months of treatment with raloxifene, a selective estrogen receptor modulator. One year later, bilateral mammoplasty was performed to remove the remaining breast tissue. Finasteride, a 5-alpha-reductase inhibitor, is widely used for the treatment of androgenetic alopecia. Gynecomastia is an expected side effect of this therapy given its mechanism of action. However, only 8 cases of gynecomastia have been reported with low-dose (1 mg daily) finasteride treatment since its approval for androgenetic alopecia in 1997. This raises the concern that gynecomastia resulting from low-dose finasteride is significantly underreported, causing inadequately informed patients. Further, because of the risk of gynecomastia, it is important for prescribing physicians to counsel patients regarding this complication and to consider early intervention when finasteride-induced gynecomastia first arises to prevent fibrosis and thus irreversible gynecomastia.

The Association of Accelerated Early Growth, Timing of Puberty, and Metabolic Consequences in Children

Accelerated early growth and early timing of puberty or pubertal variant have been noticed as risk factors for metabolic syndrome, more frequently observed in children born small for gestational age (SGA) or children with premature adrenarche (PA). Children with SGA, especially if they make an accelerated catch-up growth in early life, carry a higher risk for long-term metabolic consequences, such as type 2 diabetes, insulin resistance, and cardiovascular diseases. Furthermore, multiple studies support that these children, either born SGA or with a history of PA, may have earlier pubertal timing, which is also associated with various metabolic risks. This review aims to summarize the recent studies investigating the association between early infantile growth, the timing of puberty, and metabolic risks to expand our knowledge and gain more insight into the underlying pathophysiology.

Loss of function variant in SPIN4 causes an X-linked overgrowth syndrome

Overgrowth syndromes can be caused by pathogenic genetic variants in epigenetic writers, such as DNA and histone methyltransferases. However, no overgrowth disorder has previously been ascribed to variants in a gene that acts primarily as an epigenetic reader. Here, we studied a male individual with generalized overgrowth of prenatal onset. Exome sequencing identified a hemizygous frameshift variant in Spindlin 4 (SPIN4), with X-linked inheritance. We found evidence that SPIN4 binds specific histone modifications, promotes canonical WNT signaling, and inhibits cell proliferation in vitro and that the identified frameshift variant had lost all of these functions. Ablation of Spin4 in mice recapitulated the human phenotype with generalized overgrowth, including increased longitudinal bone growth. Growth plate analysis revealed increased cell proliferation in the proliferative zone and an increased number of progenitor chondrocytes in the resting zone. We also found evidence of decreased canonical Wnt signaling in growth plate chondrocytes, providing a potential explanation for the increased number of resting zone chondrocytes. Taken together, our findings provide strong evidence that SPIN4 is an epigenetic reader that negatively regulates mammalian body growth, and that loss of SPIN4 causes an overgrowth syndrome in humans, expanding our knowledge of the epigenetic regulation of human growth.

Effect of stimulants on final adult height

BACKGROUND

The use of stimulant medications for treatment of ADHD has raised concern as to whether they adversely impact linear growth. Previous studies have indicated that stimulant medications may suppress growth for a short period after treatment initiation; however, more information is needed to evaluate the long-term effects on final adult stature. This mini review aims to evaluate the effect of stimulant medications on final adult height in children with ADHD.

CONTENTS

We performed a literature review across PubMed/MEDLINE database. Only articles that included data on final adult height or near final adult height (age≥16 or 17 years) were included.

SUMMARY

Early studies investigating the long-term impacts of stimulant medications observed growth suppression during the active treatment period, but when comparing final adult height, there was no difference between the control and ADHD groups. A recent larger comprehensive study (Multimodal Treatment of ADHD study) has suggested that the long-term use of significant doses of stimulants during childhood may compromise final adult height to a clinically significant degree when comparing adult height across three long-term patterns of stimulant treatment (Consistent, Intermittent, Negligible). The consistent use subgroup was significantly shorter than other subgroups.

OUTLOOK

For children with ADHD, a significant long-term dose of stimulant treatment should be used with caution to avoid diminishing adult height potential. Pediatric endocrinologists should consider chronic use of stimulants as a factor contributing to reduced adult height.

RF13 | PMON133 A novel variant in an intron consensus sequence associated with familial growth hormone deficiency

Splicing variants in the exon-intron boundaries of the GH1 gene have been reported to cause autosomal dominant growth hormone deficiency (GHD type 2). However, whether variants in the intron consensus sequence (XGGG repeats) have an important role in GH1 gene splicing has not been established. Two siblings (proband 1 and 2) were diagnosed with growth hormone deficiency due to poor linear growth at age 4 years (height SDS -2.2 and – 1.6, respectively). Peak serum GH levels with provocative testing were 4.39 ng/ml and 2.77 ng/ml, respectively. They had no other pituitary hormone deficiencies and their pituitary MRIs were normal. Both children are being treated with recombinant human GH (rhGH) with excellent responses in linear growth. Their mother also had a history of GHD in childhood and received rhGH from ages 4 to 13 years. After GH treatment, she reached a normal adult height. The remainder of her pituitary function was normal. Exome sequencing was performed on the probands, their affected mother, and unaffected maternal grandparents to identify the underlying genetic cause. Exome sequencing revealed that the affected mother carried a de novo variant in intron 3 of the GH1 gene (c.291+34G>A, NM_000515.5), and the intronic variant was passed on to the two probands. The variant is not found in the general population according to gnomAD. No other variants in GH1 or other genes were detected to cosegregate with GHD in this family. The intronic variant was located in one of the two intron consensus regions in intron 3 and was predicted by ESEfinder to create a new splicing enhancer (SF2/ASF) binding site. Because intron consensus sequence repeats are important for spliceosome assembly, the variant is predicted to cause aberrant pre-mRNA splicing but not affecting the donor or acceptor site. Previously, a variant in the intron consensus sequence, c.291+28G>A, was found to cause exon 3 skipping, presumably generating a small amount of 22 kDa GH but a large amount of 17 kDa GH. Small deletions in intron 3 (c.291+28_45del and c.291+56_77del) have also been reported to cause exon 3 skipping, categorized as GHD type 2. In vitro studies with the new variant will be required to confirm exon 3 skipping as the mechanism of GHD in this family. This novel intronic variant which creates a new splicing enhancer-binding site supports the previous finding that the intron consensus sequence plays a significant role in the splicing of GH1 pre-mRNA and results in autosomal dominant GHD. As other variants in intron consensus sequence sites may cause GHD type 2, we recommend genetic testing in patients with GHD include the intron consensus sequence regions.

Presentation: Sunday, June 12, 2022 12:48 p.m. - 12:53 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

A neomorphic variant in SP7 alters sequence specificity and causes a high-turnover bone disorder

SP7/Osterix is a transcription factor critical for osteoblast maturation and bone formation. Homozygous loss-of-function mutations in SP7 cause osteogenesis imperfecta type XII, but neomorphic (gain-of-new-function) mutations of SP7 have not been reported in humans. Here we describe a de novo dominant neomorphic missense variant (c.926 C > G:p.S309W) in SP7 in a patient with craniosynostosis, cranial hyperostosis, and long bone fragility. Histomorphometry shows increased osteoblasts but decreased bone mineralization. Mice with the corresponding variant also show a complex skeletal phenotype distinct from that of Sp7-null mice. The mutation alters the binding specificity of SP7 from AT-rich motifs to a GC-consensus sequence (typical of other SP family members) and produces an aberrant gene expression profile, including increased expression of Col1a1 and endogenous Sp7, but decreased expression of genes involved in matrix mineralization. Our study identifies a pathogenic mechanism in which a mutation in a transcription factor shifts DNA binding specificity and provides important in vivo evidence that the affinity of SP7 for AT-rich motifs, unique among SP proteins, is critical for normal osteoblast differentiation.

Evidence That the Etiology of Congenital Hypopituitarism Has a Major Genetic Component but Is Infrequently Monogenic

Purpose

Congenital hypopituitarism usually occurs sporadically. In most patients, the etiology remains unknown.

Methods

We studied 13 children with sporadic congenital hypopituitarism. Children with non-endocrine, non-familial idiopathic short stature (NFSS) (n = 19) served as a control group. Exome sequencing was performed in probands and both unaffected parents. A burden testing approach was used to compare the number of candidate variants in the two groups.

Results

First, we assessed the frequency of rare, predicted-pathogenic variants in 42 genes previously reported to be associated with pituitary gland development. The average number of variants per individual was greater in probands with congenital hypopituitarism than those with NFSS (1.1 vs. 0.21, mean variants/proband, P = 0.03). The number of probands with at least 1 variant in a pituitary-associated gene was greater in congenital hypopituitarism than in NFSS (62% vs. 21%, P = 0.03). Second, we assessed the frequency of rare, predicted-pathogenic variants in the exome (to capture undiscovered causes) that were inherited in a fashion that could explain the sporadic occurrence of the proband's condition with a monogenic etiology (de novo mutation, autosomal recessive, or X-linked recessive) with complete penetrance. There were fewer monogenic candidates in the probands with congenital hypopituitarism than those with NFSS (1.3 vs. 2.5 candidate variants/proband, P = 0.024). We did not find any candidate variants (0 of 13 probands) in genes previously reported to explain the phenotype in congenital hypopituitarism, unlike NFSS (8 of 19 probands, P = 0.01).

Conclusion

Our findings provide evidence that the etiology of sporadic congenital hypopituitarism has a major genetic component but may be infrequently monogenic with full penetrance, suggesting a more complex etiology.

Genetic evaluation in children with short stature

PURPOSE OF REVIEW

Short stature is a common clinical manifestation in children. Yet, a cause is often unidentifiable in the majority of children with short stature by a routine screening approach. The purpose of this review is to describe the optimal genetic approach for evaluating short stature, challenges of genetic testing, and recent advances in genetic testing for short stature.

RECENT FINDINGS

Genetic testing, such as karyotype, chromosomal microarray, targeted gene sequencing, or exome sequencing, has served to identify the underlying genetic causes of short stature. When determining which short stature patient would benefit from genetic evaluation, it is important to consider whether the patient would have a single identifiable genetic cause. Specific diagnoses permit clinicians to predict responses to growth hormone treatment, to understand the phenotypic spectrum, and to understand any associated co-morbidities.

SUMMARY

The continued progress in the field of genetics and enhanced capabilities provided by genetic testing methods expands the ability of physicians to evaluate children with short stature for underlying genetic defects. Continued effort is needed to elaborate new genetic causes of linear growth disorders, therefore, we expand the list of known genes for short stature, which will subsequently increase the rate of genetic diagnosis for children with short stature.

Exploring the Potential Role of DLK1 in Pubertal Initiation

The mechanisms that orchestrate the initiation of puberty are not well understood. DLK1 encodes a transmembrane protein that interacts with NOTCH1 receptor to negatively regulate NOTCH signaling. Loss-of-function mutations in DLK1 cause central precocious puberty, suggesting that DLK1 normally inhibits the reproductive axis centrally. The soluble form of DLK1, which is generated by proteolytic cleavage of the DLK1 extracellular domain, is measurable in human serum. We hypothesized that serum soluble DLK1 concentrations decline with age and that the decline, either in circulating levels or in tissue expression, contributes to the physiological mechanisms triggering pubertal initiation. Serum DLK1 was measured by immunoassay in 102 healthy subjects (age newborn - 26 yrs, 54 male). DLK1 concentrations did not differ by sex, BMI SDS, height, or status of fasting. DLK1 concentrations declined overall with age (R2=0.04, P<0.001). However, there was not a substantial decline in the peripubertal period (mean± SEM, at Tanner stage 1, 2, 3, 4, 5: 14.8 ± 1.9, 16.4 ± 1.2, 17.0 ± 5, 13.6 ± 3, 9.7 ± 0.9 ng/mL). Serum DLK1, measured in 12 subjects (2 male) with a previous history of idiopathic central precocious puberty, did not differ from healthy controls. We next hypothesized that declining expression of Dlk1 or increasing expression of competing canonical NOTCH ligands in hypothalamus contributes to pubertal onset. The preoptic area (POA) was microdissected from rat brains (age 4 d, 2 w, 6 w, and 8-16 w, n=5 each) and expression was measured by RT-PCR. Dlk1 expression increased with age in both female and male rats (P<0.001). Notch1 expression did not change with age. Expression of two ligands, Jag1 and Dll4, showed a peak at age 6 w, around the time of puberty, but only in males, and none of the other ligands (Jag1, Dll1, and Dll3) showed increasing expression at the age of puberty. In conclusion, we did not find evidence that declining serum soluble DLK1 concentrations in humans, declining DLK1 expression in rat preoptic area, or increasing NOTCH ligand expression in rat preoptic area contribute to pubertal onset.

SAT-289 Evidence That Combined Pituitary Hormone Deficiency Frequently Has a Digenic/Oligogenic Etiology

Congenital hypopituitarism usually occurs in a child without a family history of pituitary disease. Explanations for such sporadic occurrence include: 1) monogenic inheritance (recessive or de novo), 2) digenic/oligogenic inheritance, and/or 3) nongenetic factors. To help distinguish these possibilities, we studied 9 children with hypopituitarism (HP)(small anterior pituitary gland, ectopic posterior pituitary, and either isolated GH deficiency (n=1) or combined with other pituitary hormone deficiencies(n=8)), with non-consanguineous parents and no family history of pituitary disease. SNP array analyses confirmed paternity and non-consanguinity and excluded significant copy-number variation. Exome sequencing was performed in probands and parents. Candidate variants (coverage >10, confirmed by examining BAM files, population frequency <1%, <2 homozygous subjects in gnomAD, and pathogenic prediction by at least 2 out of 3 prediction algorithms (SIFT, MutationTaster, PolyPhen2)) were identified. Children with non-familial non-endocrine idiopathic short stature (ISS) (n=19, sequenced at the same laboratory followed by simultaneous data processing with HP patients), served as a control group. To assess the frequency of genetic (mono-, di-, or oligogenic) HP cases, we identified heterozygous variants (regardless of inheritance) in 42 genes previously reported to be associated with pituitary development. The average number of variants per proband was greater in HP than in ISS (1.1 vs 0.26, P = 0.04). Similarly, the number of probands with at least 1 variant in a pituitary-associated gene was greater in HP than in ISS (67% vs 21%, P = 0.035). These data suggest that sporadic hypopituitarism is frequently genetic. To assess the number of monogenic cases, we counted the number of candidate variants (in any gene in the genome, to capture undiscovered causes) that were inherited in a fashion that could explain the sporadic occurrence with a monogenic etiology (de novo mutation, autosomal recessive, X-linked recessive). There were fewer monogenic candidates in subjects with HP than ISS (1.6 vs 2.6 candidates/proband, P = 0.03). These data are consistent with approximately 1.6 non-causative variants/proband in both groups plus approximately 1 causative monogenic variant in ISS vs approximately 0 causative monogenic variants in HP. Candidate variants in genes previously reported to explain the phenotype were identified in 0 out of 9 trios with HP and in 8 of 19 trios with ISS (42%). These findings suggest that a monogenic inheritance is less common in HP than in ISS. In conclusion, the findings suggest that sporadic congenital hypopituitarism is frequently genetic but infrequently monogenic, implying a likely digenic/oligogenic etiology.

DLG2 variants in patients with pubertal disorders

PURPOSE

Impaired function of gonadotropin-releasing hormone (GnRH) neurons can cause a phenotypic spectrum ranging from delayed puberty to isolated hypogonadotropic hypogonadism (IHH). We sought to identify a new genetic etiology for these conditions.

METHODS

Exome sequencing was performed in an extended family with autosomal dominant, markedly delayed puberty. The effects of the variant were studied in a GnRH neuronal cell line. Variants in the same gene were sought in a large cohort of individuals with IHH.

RESULTS

We identified a rare missense variant (F900V) in DLG2 (which encodes PSD-93) that cosegregated with the delayed puberty. The variant decreased GnRH expression in vitro. PSD-93 is an anchoring protein of NMDA receptors, a type of glutamate receptor that has been implicated in the control of puberty in laboratory animals. The F900V variant impaired the interaction between PSD-93 and a known binding partner, Fyn, which phosphorylates NMDA receptors. Variants in DLG2 that also decreased GnRH expression were identified in three unrelated families with IHH.

CONCLUSION

The findings indicate that variants in DLG2/PSD-93 cause autosomal dominant delayed puberty and may also contribute to IHH. The findings also suggest that the pathogenesis involves impaired NMDA receptor signaling and consequently decreased GnRH secretion.

Plasma midkine concentrations in healthy children, children with increased and decreased adiposity, and children with short stature

BACKGROUND

Midkine (MDK), one of the heparin-binding growth factors, is highly expressed in multiple organs during embryogenesis. Plasma concentrations have been reported to be elevated in patients with a variety of malignancies, in adults with obesity, and in children with short stature, diabetes, and obesity. However, the concentrations in healthy children and their relationships to age, nutrition, and linear growth have not been well studied.

SUBJECTS AND METHODS

Plasma MDK was measured by immunoassay in 222 healthy, normal-weight children (age 0-18 yrs, 101 boys), 206 healthy adults (age 18-91 yrs, 60 males), 61 children with BMI ≥ 95th percentile (age 4-18 yrs, 20 boys), 20 girls and young women with anorexia nervosa (age 14-23 yrs), and 75 children with idiopathic short stature (age 3-18 yrs, 42 boys). Body fat was evaluated by dual-energy X-ray absorptiometry (DXA) in a subset of subjects. The associations of MDK with age, sex, adiposity, race/ethnicity and stature were evaluated.

RESULTS

In healthy children, plasma MDK concentrations declined with age (r = -0.54, P < 0.001) with values highest in infants. The decline occurred primarily during the first year of life. Plasma MDK did not significantly differ between males and females or between race/ethnic groups. MDK concentrations were not correlated with BMI SDS, fat mass (kg) or percent total body fat, and no difference in MDK was found between children with anorexia nervosa, healthy weight and obesity. For children with idiopathic short stature, MDK concentrations did not differ significantly from normal height subjects, or according to height SDS or IGF-1 SDS.

CONCLUSIONS

In healthy children, plasma MDK concentrations declined with age and were not significantly associated with sex, adiposity, or stature-for-age. These findings provide useful reference data for studies of plasma MDK in children with malignancies and other pathological conditions.

Genetic regulation of linear growth

Linear growth occurs at the growth plate. Therefore, genetic defects that interfere with the normal function of the growth plate can cause linear growth disorders. Many genetic causes of growth disorders have already been identified in humans. However, recent genome-wide approaches have broadened our knowledge of the mechanisms of linear growth, not only providing novel monogenic causes of growth disorders but also revealing single nucleotide polymorphisms in genes that affect height in the general population. The genes identified as causative of linear growth disorders are heterogeneous, playing a role in various growth-regulating mechanisms including those involving the extracellular matrix, intracellular signaling, paracrine signaling, endocrine signaling, and epigenetic regulation. Understanding the underlying genetic defects in linear growth is important for clinicians and researchers in order to provide proper diagnoses, management, and genetic counseling, as well as to develop better treatment approaches for children with growth disorders.

QRICH1 mutations cause a chondrodysplasia with developmental delay

In many children with short stature, the etiology of the decreased linear growth remains unknown. We sought to identify the underlying genetic etiology in a patient with short stature, irregular growth plates of the proximal phalanges, developmental delay, and mildly dysmorphic facial features. Exome sequencing identified a de novo, heterozygous, nonsense mutation (c.1606C>T:p.R536X) in QRICH1. In vitro studies confirmed that the mutation impaired expression of the QRICH1 protein. SiRNA-mediated knockdown of Qrich1 in primary mouse epiphyseal chondrocytes caused downregulation of gene expression associated with hypertrophic differentiation. We then identified an unrelated individual with another heterozygous de novo nonsense mutation in QRICH1 who had a similar phenotype. A recently published study identified QRICH1 mutations in three patients with developmental delay, one of whom had short stature. Our findings indicate that QRICH1 mutations cause not only developmental delay but also a chondrodysplasia characterized by diminished linear growth and abnormal growth plate morphology due to impaired growth plate chondrocyte hypertrophic differentiation.

Differential aging of growth plate cartilage underlies differences in bone length and thus helps determine skeletal proportions

Bones at different anatomical locations vary dramatically in size. For example, human femurs are 20-fold longer than the phalanges in the fingers and toes. The mechanisms responsible for these size differences are poorly understood. Bone elongation occurs at the growth plates and advances rapidly in early life but then progressively slows due to a developmental program termed “growth plate senescence.” This developmental program includes declines in cell proliferation and hypertrophy, depletion of cells in all growth plate zones, and extensive underlying changes in the expression of growth-regulating genes. Here, we show evidence that these functional, structural, and molecular senescent changes occur earlier in the growth plates of smaller bones (metacarpals, phalanges) than in the growth plates of larger bones (femurs, tibias) and that this differential aging contributes to the disparities in bone length. We also show evidence that the molecular mechanisms that underlie the differential aging between different bones involve modulation of critical paracrine regulatory pathways, including insulin-like growth factor (Igf), bone morphogenetic protein (Bmp), and Wingless and Int-1 (Wnt) signaling. Taken together, the findings reveal that the striking disparities in the lengths of different bones, which characterize normal mammalian skeletal proportions, is achieved in part by modulating the progression of growth plate senescence.

The various bones found in human extremities vary dramatically in size. For example, the femur in the thigh is approximately 20 times longer than the phalanges of the toes. The mechanisms that regulate how much a particular bone grows to attain the skeletal proportions of each animal remain mostly unknown. In this study, we sought to uncover these mechanisms and found that this scaling in skeletal size is achieved in part by modulating the rate of aging of growth plates in different bones. Bone elongation occurs at the cartilaginous growth plates and proceeds rapidly in early life but slows and eventually stops due to a developmental program termed “growth plate senescence,” which is used to describe the gradual decline in growth plate function with age. We discovered that this developmental program is more advanced in shorter bones than in longer bones and that this differential aging contributes to the disparities in bone growth. We show that the molecular mechanisms that underlie this differential aging between bones involve differential expression of specific local signaling pathways, which regulate cell proliferation and differentiation in the growth plate. Taken together, we conclude that the striking disparities in the lengths of different bones—characteristic of normal mammalian skeletal proportions—are achieved in part by modulating the progression of aging in the growth plates.

New Genetic Diagnoses of Short Stature Provide Insights into Local Regulation of Childhood Growth

Idiopathic short stature is a common condition with a heterogeneous etiology. Advances in genetic methods, including genome sequencing techniques and bioinformatics approaches, have emerged as important tools to identify the genetic defects in families with monogenic short stature. These findings have contributed to the understanding of growth regulation and indicate that growth plate chondrogenesis, and therefore linear growth, is governed by a large number of genes important for different signaling pathways and cellular functions, including genetic defects in hormonal regulation, paracrine signaling, cartilage matrix, and fundamental cellular processes. In addition, mutations in the same gene can cause a wide phenotypic spectrum depending on the severity and mode of inheritance of the mutation.
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mir-374-5p, mir-379-5p, and mir-503-5p Regulate Proliferation and Hypertrophic Differentiation of Growth Plate Chondrocytes in Male Rats

Growth plate chondrocytes undergo sequential differentiation to form the resting zone, the proliferative zone (PZ), and the hypertrophic zone (HZ). The important role of microRNAs (miRNAs) in the growth plate was previously revealed by cartilage-specific ablation of Dicer, an enzyme essential for biogenesis of many miRNAs. To identify specific miRNAs that regulate differentiation of PZ chondrocytes to HZ chondrocytes, we microdissected individual growth plate zones from juvenile rats and performed miRNA profiling using a solution hybridization method and miRNA sequencing. Thirty-four miRNAs were differentially expressed between the PZ and the HZ, and we hypothesized that some of the miRNAs that are preferentially expressed in the PZ may promote proliferation and inhibit hypertrophic differentiation. Consistent with this hypothesis, transfection of inhibitors for four of these miRNAs (mir-369-3p, mir-374-5p, mir-379-5p, and mir-503-5p) decreased proliferation in primary epiphyseal chondrocytes. The inhibitors for three of these miRNAs (mir-374-5p, mir-379-5p, and mir-503-5p) also increased expression of multiple genes that are associated with chondrocyte hypertrophic differentiation. We next hypothesized that preferential expression of these miRNAs in the PZ is driven by the parathyroid hormone-related protein (PTHrP) concentration gradient across the growth plate. Consistent with this hypothesis, treatment of primary chondrocytes with a parathyroid hormone (PTH)/PTHrP receptor agonist, PTH1-34, increased expression of mir-374-5p, mir-379-5p, and mir-503-5p. Taken together, our findings suggest that the PTHrP concentration gradient across the growth plate induces differential expression of mir-374-5p, mir-379-5p, and mir-503-5p between the PZ and the HZ. In the PZ, the higher expression levels of these miRNAs promote proliferation and inhibit hypertrophic differentiation. In the HZ, downregulation of these miRNAs inhibits proliferation and promotes hypertrophic differentiation.

Midkine and pleiotrophin concentrations in needle biopsies of breast and lung masses

BACKGROUND/OBJECTIVE

Midkine (MDK) and pleiotrophin (PTN) are two closely related heparin-binding growth factors which are overexpressed in a wide variety of human cancers. We hypothesized that the concentrations of these factors in washout of biopsy needles would be higher in breast and lung cancer than in benign lesions.

METHODS

Seventy subjects underwent pre-operative core needle biopsies of 78 breast masses (16 malignancies). In 11 subjects, fine needle aspiration was performed ex vivo on 7 non-small cell lung cancers and 11 normal lung specimens within surgically excised lung tissue. The biopsy needle was washed with buffer for immunoassay.

RESULTS

The MDK/DNA and the PTN/DNA ratio in most of the malignant breast masses were similar to the ratios in benign masses except one lobular carcinoma in situ (24-fold higher PTN/DNA ratio than the average benign mass). The MDK/DNA and PTN/DNA ratio were similar in most malignant and normal lung tissue except one squamous cell carcinoma (38-fold higher MDK/DNA ratio than the average of normal lung tissue).

CONCLUSIONS

Both MDK and PTN are readily measurable in washout of needle biopsy samples from breast and lung masses and levels are highly elevated only in a specific subset of these malignancies.

Aggrecan Mutations in Nonfamilial Short Stature and Short Stature Without Accelerated Skeletal Maturation

Aggrecan, a proteoglycan, is an important component of cartilage extracellular matrix, including that of the growth plate. Heterozygous mutations in ACAN, the gene encoding aggrecan, cause autosomal dominant short stature, accelerated skeletal maturation, and joint disease. The inheritance pattern and the presence of bone age equal to or greater than chronological age have been consistent features, serving as diagnostic clues. From family 1, a 6-year-old boy presented with short stature [height standard deviation score (SDS), −1.75] and bone age advanced by 3 years. There was no family history of short stature (height SDS: father, −0.76; mother, 0.7). Exome sequencing followed by Sanger sequencing identified a de novo novel heterozygous frameshift mutation in ACAN (c.6404delC: p.A2135Dfs). From family 2, a 12-year-old boy was evaluated for short stature (height SDS, −3.9). His bone age at the time of genetic evaluation was approximately 1 year less than his chronological age. Family history was consistent with an autosomal dominant inheritance of short stature, with several affected members also showing early-onset osteoarthritis. Exome sequencing, confirmed by Sanger sequencing, identified a novel nonsense mutation in ACAN (c.4852C>T: p.Q1618X), which cosegregated with the phenotype. In conclusion, patients with ACAN mutations may present with nonfamilial short stature and with bone age less than chronological age. These findings expand the known phenotypic spectrum of heterozygous ACAN mutations and indicate that this diagnosis should be considered in children without a family history of short stature and in children without accelerated skeletal maturation.

Genetics of Short Stature

Short stature is a common and heterogeneous condition that is often genetic in etiology. For most children with genetic short stature, the specific molecular causes remain unknown; but with advances in exome/genome sequencing and bioinformatics approaches, new genetic causes of growth disorders have been identified, contributing to the understanding of the underlying molecular mechanisms of longitudinal bone growth and growth failure. Identifying new genetic causes of growth disorders has the potential to improve diagnosis, prognostic accuracy, and individualized management, and help avoid unnecessary testing for endocrine and other disorders.

Combined pituitary hormone deficiency in a girl with 48, XXXX and Rathke's cleft cyst

BACKGROUND

Tetrasomy X is a rare chromosomal aneuploidy seen in girls, associated with facial dysmorphism, premature ovarian insufficiency and intellectual disability. A Rathke's cleft cyst (RCC) is a remnant of Rathke's pouch which may cause multiple pituitary hormone deficiencies by exerting pressure on the pituitary gland in the sella.

METHODS/RESULTS

The patient was diagnosed with tetrasomy X by karyotyping during infancy. Brain MRI and multiple endocrine stimulation tests revealed RCC and combined pituitary hormone deficiency (growth hormone deficiency, secondary adrenal insufficiency and central hypothyroidism) likely due to RCC.

CONCLUSION

We report the first case in the literature of a girl with 48, XXXX and combined pituitary hormone deficiency due to Rathke's cyst.

BRF1 mutations in a family with growth failure, markedly delayed bone age, and central nervous system anomalies

Linear growth failure can be caused by many different genetic abnormalities. In many cases, the genetic defect affects not only the growth plate, causing short stature but also other organs/tissues causing additional clinical abnormalities. A 10-year old boy was evaluated for impaired postnatal linear growth (height 113.3 cm, -4.6 SDS), a bone age that was delayed by 5 years, dysmorphic facies, cognitive impairment, and central nervous system anomalies. His younger brother, presented only with growth failure at 10 months of age. Exome sequencing identified compound heterozygous variants in the gene encoding RNA polymerase III transcription initiation factor 90 kDa subunit (BRF1) in both affected siblings: a missense mutation (c.875 C > G:p.P292R) and a frameshift mutation (c.551delG:p.C184Sfs). The frameshift mutation is expected to lead to nonsense-mediated mRNA decay (NMD) and/or to protein truncation. Expression of BRF1 with the P292R missense mutation failed to rescue yeast lacking BRF1. The findings confirm a previous report showing that biallelic mutations in BRF1 cause cerebellar-facial-dental syndrome. Our findings also help define the growth phenotype, indicating that the linear growth failure can become clinically evident before the neurological abnormalities and that a severely delayed bone age may serve as a diagnostic clue.

EZH1 and EZH2 promote skeletal growth by repressing inhibitors of chondrocyte proliferation and hypertrophy

Histone methyltransferases EZH1 and EZH2 catalyse the trimethylation of histone H3 at lysine 27 (H3K27), which serves as an epigenetic signal for chromatin condensation and transcriptional repression. Genome-wide associated studies have implicated EZH2 in the control of height and mutations in EZH2 cause Weaver syndrome, which includes skeletal overgrowth. Here we show that the combined loss of Ezh1 and Ezh2 in chondrocytes severely impairs skeletal growth in mice. Both of the principal processes underlying growth plate chondrogenesis, chondrocyte proliferation and hypertrophy, are compromised. The decrease in chondrocyte proliferation is due in part to derepression of cyclin-dependent kinase inhibitors Ink4a/b, while ineffective chondrocyte hypertrophy is due to the suppression of IGF signalling by the increased expression of IGF-binding proteins. Collectively, our findings reveal a critical role for H3K27 methylation in the regulation of chondrocyte proliferation and hypertrophy in the growth plate, which are the central determinants of skeletal growth.

Accelerated Skeletal Maturation in Disorders of Retinoic Acid Metabolism: A Case Report and Focused Review of the Literature

Nutritional excess of vitamin A, a precursor for retinoic acid (RA), causes premature epiphyseal fusion, craniosynostosis, and light-dependent retinopathy. Similarly, homozygous loss-of-function mutations in CYP26B1, one of the major RA-metabolizing enzymes, cause advanced bone age, premature epiphyseal fusion, and craniosynostosis. In this paper, a patient with markedly accelerated skeletal and dental development, retinal scarring, and autism-spectrum disease is presented and the role of retinoic acid in longitudinal bone growth and skeletal maturation is reviewed. Genetic studies were carried out using SNP array and exome sequencing. RA isomers were measured in the patient, family members, and in 18 age-matched healthy children using high-performance liquid chromatography coupled to tandem mass spectrometry. A genomic SNP array identified a novel 8.3 megabase microdeletion on chromosome 10q23.2-23.33. The 79 deleted genes included CYP26A1 and C1, both major RA-metabolizing enzymes. Exome sequencing did not detect any variants that were predicted to be deleterious in the remaining alleles of these genes or other known retinoic acid-metabolizing enzymes. The patient exhibited elevated plasma total RA (16.5 vs. 12.6±1.5 nM, mean±SD, subject vs. controls) and 13-cisRA (10.7 nM vs. 6.1±1.1). The findings support the hypothesis that elevated RA concentrations accelerate bone and dental maturation in humans. CYP26A1 and C1 haploinsufficiency may contribute to the elevated retinoic acid concentrations and clinical findings of the patient, although this phenotype has not been reported in other patients with similar deletions, suggesting that other unknown genetic or environmental factors may also contribute.

Midkine and Pleiotrophin Concentrations in Amniotic Fluid in Healthy and Complicated Pregnancies

Background

Midkine (MDK) and pleiotrophin (PTN) are heparin-binding growth factors that, in rodents, are highly expressed in early life and decrease to undetectable levels by adulthood. The potential roles of MDK and PTN in human growth and development are not completely elucidated.

Method and Findings

To delineate the role of MDK and PTN in human development, we developed high sensitivity assays to measure their concentrations in amniotic fluid (AF) at various gestational ages in both healthy and complicated pregnancies. We found that both of these growth factors could be readily measured in AF and that the concentrations were higher than most cytokines previously reported in AF.

Conclusion

The concentration of MDK but not that of PTN declined with gestational age. Both MDK and PTN concentrations were found to be lower in pregnancies that were complicated by chorioamnionitis at term, raising the possibility that these growth factors might be useful as markers for infection.

Increased Pleiotrophin Concentrations in Papillary Thyroid Cancer

Background

Thyroid nodules are common, and approximately 5% of these nodules are malignant. Pleiotrophin (PTN) is a heparin-binding growth factor which is overexpressed in many cancers. The expression of PTN in papillary thyroid cancer (PTC) is unknown.

Method and Findings

74 subjects (age 47 ± 12 y, 15 males) who had thyroidectomy with a histological diagnosis: 79 benign nodules and 23 PTCs (10 classic, 6 tall cell, 6 follicular variant and 1 undetermined). Fine-needle aspiration (FNA) samples were obtained ex vivo from surgically excised tissue and assayed for PTN and thyroglobulin (Tg). Immunohistochemistry (IHC) was performed on tissue sections. In FNA samples, PTN concentration normalized to Tg was significantly higher in PTC than in benign nodules (16 ± 6 vs 0.3 ± 0.1 ng/mg, p < 0.001). In follicular variant of PTC (n = 6), the PTN/Tg ratio was also higher than in benign nodules (1.3 ± 0.6 vs 0.3 ± 0.1 ng/mg, P < 0.001, respectively). IHC showed cytoplasmic localization of PTN in PTC cells.

Conclusion

In ex vivo FNA samples, the PTN to thyroglobulin ratio was higher in PTCs, including follicular variant PTC, than in benign thyroid nodules. The findings raise the possibility that measurement of the PTN to Tg ratio may provide useful diagnostic and/or prognostic information in the evaluation of thyroid nodules.

Midkine concentrations in fine-needle aspiration of benign and malignant thyroid nodules

CONTEXT

The primary preoperative method for distinguishing malignant from benign thyroid nodules is fine-needle aspiration (FNA) cytology, but it is frequently inconclusive. Midkine (MDK) is a heparin-binding growth factor, which is overexpressed in papillary thyroid carcinoma (PTC).

OBJECTIVE

We measured MDK concentrations in FNA samples from benign and malignant thyroid nodules to explore the possibility that MDK measurement might aid in the evaluation of thyroid nodules.

DESIGN

35 subjects underwent preoperative FNA of 45 thyroid nodules, followed by thyroidectomy, providing a histological diagnosis. FNA needle contents were first expressed for cytology, and then, the needle was washed with buffer for immunoassay. In 46 subjects without preoperative FNA samples, FNA was performed ex vivo on 62 nodules within surgically excised thyroid tissue.

MEASUREMENTS

MDK was measured using a high-sensitivity sandwich ELISA and normalized to thyroglobulin (Tg) concentration in the sample to adjust for tissue content in the aspirate.

RESULTS

The MDK/Tg ratio was higher in 18 PTCs than in 87 benign nodules (204 ± 106 vs 1·2 ± 0·3 ng/mg, mean ± SEM, P < 0·001). Using a threshold of 10 ng/mg, the sensitivity and specificity of the MDK/Tg ratio for diagnosis of PTC were 67% and 99%, respectively. All follicular variant PTCs had a MDK/Tg ratio <10 ng/mg.

CONCLUSIONS

The findings indicate that, in FNA samples, the MDK/Tg ratio in PTC is greater than in benign thyroid nodules, raising the possibility that this approach might provide adjunctive diagnostic or prognostic information to complement existing approaches.

A novel frame shift mutation in the GHRH receptor gene in familial isolated GH deficiency: early occurrence of anterior pituitary hypoplasia

BACKGROUND

Mutations in the genes encoding for GHRH receptor (GHRHR) and GH (GH1) are the most common cause of familial isolated GH deficiency (IGHD). GHRHR mutations are often associated with anterior pituitary hypoplasia (APH), but this has been reported almost exclusively in children older than 8 yr. We analyzed the GHRHR and measured pituitary size in a consanguineous family with the father and three of the five siblings with IGHD.

OBJECTIVE

The aim of the study was to find the mutated gene in a family with severe IGHD.

METHODS

We sequenced the whole GHRHR coding regions and the intron-exon boundaries from peripheral DNA of the index patient. After identifying the novel mutation, we sequenced the region of interest in the other members of the family. We measured the anterior pituitary volume from magnetic resonance imaging (MRI).

RESULTS

The father and the three affected children were homozygous for a new frame-shift mutation in the coding sequence of exon 4 (corresponding to the extracellular domain of the receptor) (c.340delG) that places the downstream sequence out of frame [corrected]. The mother and two unaffected siblings were heterozygous for the mutation. Two of the affected children had MRI evidence of APH before reaching 6 yr of age.

CONCLUSIONS

We describe a new mutation in the GHRHR in a family with IGHD. The presence of frank APH before age 6 yr shows that MRI-evident reduced pituitary size can be present in GHRHR mutations even in children younger than 8 yr of age.

Spironolactone ameliorates renal injury and connective tissue growth factor expression in type II diabetic rats

Administration of spironolactone provides a beneficial effect in various animal models of renal injury. In this study, we investigated whether spironolactone prevents the progression of diabetic nephropathy through reduction of connective tissue growth factor (CTGF) synthesis in type II diabetic rats. In addition, we evaluated the effect of aldosterone and spironolactone on CTGF and collagen production in cultured cells. Renal functional and morphologic changes were examined in Otsuka Long-Evans Tokushima Fatty rats with or without spironolactone treatment (20 mg/kg/day) for 8 months, as well as in non-diabetic age-matched Long-Evans Tokushima Otsuka rats. Spironolactone treatment did not induce any significant differences in body weight, kidney/body weight ratio, serum creatinine concentration, blood glucose levels, or systolic blood pressure. However, urinary protein and albumin excretion were significantly decreased in the spironolactone treatment group, which was associated with amelioration of glomerulosclerosis. In addition, renal CTGF, collagen synthesis demonstrated marked decreases in the spironolactone treatment group. In cultured MC and PTC, aldosterone induced significant increases in CTGF gene expression and protein synthesis associated with increased collagen synthesis, which was abolished by prior treatment with spironolactone. However, aldosterone treatment did not induce transforming growth factor (TGF)-beta1 overproduction, and inhibition of TGF-beta1 by neutralization of TGF-beta1 protein did not significantly prevent aldosterone-induced CTGF production. These results suggest that the antifibrotic effects of spironolactone may be mediated by CTGF through a TGF-beta1-independent pathway in this animal model of diabetic nephropathy.

Protective effect of growth hormone on neuronal apoptosis after hypoxia-ischemia in the neonatal rat brain

Recent studies have shown that growth hormone (GH) can reduce neuronal loss after hypoxic-ischemic injury (HI) in neonatal and juvenile rat brains. Here, we investigated whether GH exerts its neuroprotective role through an anti-apoptotic effect in neonatal rat brains damaged by severe HI. Gross and histological observations showed that the extent of brain damage was found to be reduced in GH-treated brain at E7 after injury. In a terminal transferase-mediated dUTP nick-end-labeling (TUNEL) study, TUNEL-positive apoptotic cells were localized only at the damaged region in animals treated with saline, which was confirmed by an electron microscopy. In an immunohistochemical study with anti-bcl-2, -bax, -bad, -neuronal nitric oxide synthase (nNOS), -inducible NOS (iNOS) and -endothelial NOS (eNOS) antibodies, we observed that bax, bad, iNOS and eNOS were elevated in the saline-treated group. This study thus suggests that the protective role of GH against HI injury is mediated thorough an anti-apoptotic effect, which offers the possibility of a GH application for the treatment of neonatal HI encephalopathy.

Multiple Congenital Malformation in a Holstein Calf

A 10-day-old male Holstein dairy calf with orthopaedic abnormalities was unable to stand but was alert with a suckle reflex. At necropsy, the calf showed multiple defects, including partial agenesis of the left rib plate, deformed left scapula, shortened left humerus, agenesis of the left kidney, atresia ani and scoliosis. The cause of these anomalies could not be determined. This report is the first to describe partial agenesis of ribs in a calf.