RESUMO
Objective: To investigate the efficacy of monotherapy with AIs or GnRHa in improving the height of boys with idiopathic short stature (ISS). Method: We performed a systematic search in Pubmed, The Cochrane Library, Chinese National Knowledge Infrastructure databases, and Wanfang Database for eligible studies. The network meta-analysis was conducted using STATA software. Results: We identified a total of four studies that included 136 individuals. We used FAH/PAH as the main outcome of final height. The results revealed a statistically higher final height after treatment with AI or GnRHa in idiopathic short stature children(MD= 4.63, 95% CI[3.29,5.96]). In network meta-analysis, the direct and indirect comparison between AI and GnRHa was presented in the forest plot. Compared with control group, both AI and GnRHa were effective in increasing the final height, with the mean effect of 4.91(95%CI:1.10,8.17) and 5.55(95%CI:1.12,9.98) respectively. However, there was no statistical difference between the GnRHa and AI treatment, of which the mean effect was 0.65(95%CI: -4.30,5.60). Conclusion: Both AIs and GnRHa monotherapy were effective in augmenting the final height of boys with idiopathic short stature when compared to placebo groups. However, there was no statistical difference between the GnRHa and AI treatments.
Assuntos
Nanismo , Hormônio do Crescimento Humano , Masculino , Criança , Humanos , Inibidores da Aromatase , Hormônio Liberador de Gonadotropina , Metanálise em Rede , EstaturaRESUMO
Controlling the tree size of fruit species such as peach can reduce the amount of labor and input needed for orchard management. The phytohormone gibberellin (GA) positively regulates tree size by inducing degradation of the GA signaling repressor DELLA. The N-terminal DELLA domain in this protein is critical for its GA-dependent interaction with the GA receptor GID1 and the resulting degradation of the DELLA protein, which allows for growth-promoting GA signaling. In this study, a DELLA family member, PpeDGYLA, contains a DELLA domain but has amino acid changes in three conserved motifs (DELLA into DGYLA, LEQLE into LERLE, and TVHYNP into AVLYNP). In the absence or presence of GA3, the PpeDGYLA protein did not interact with PpeGID1c and was stable in 35S-PpeDGYLA peach transgenic callus. The overexpression of PpeDGYLA in both polar and Arabidopsis showed an extremely dwarfed phenotype, and these transgenic plants were insensitive to GA3 treatment. PpeDGYLA could interact with PpeARF6-1 and -2, supposed growth-promoting factors. It is suggested that the changes in the DELLA domain of PpeDGYLA may, to some extent, account for the severe dwarf phenotype of poplar and Arabidopsis transgenic plants. In addition, our study showed that the DELLA family contained three clades (DELLA-like, DELLA, and DGLLA). PpeDGYLA clustered into the DGLLA clade and was expressed in all of the analyzed tissues. These results lay the foundation for the further study of the repression of tree size by PpeDGYLA.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Nanismo , Prunus persica , Arabidopsis/metabolismo , Prunus persica/genética , Prunus persica/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Giberelinas/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
SHOX deficiency is a common genetic cause of short stature of variable degree. SHOX haploinsufficiency causes Leri-Weill dyschondrosteosis (LWD) as well as nonspecific short stature. SHOX haploinsufficiency is known to result from heterozygous loss-of-function variants with pseudo-autosomal dominant inheritance, while biallelic SHOX loss-of-function variants cause the more severe skeletal dysplasia, Langer mesomelic dyschondrosteosis (LMD). Here we report for the first time the pseudo-autosomal recessive inheritance of LWD in two siblings caused by a novel homozygous non-canonical, leaky splice-site variant in intron 3 of SHOX: c.544+5G>C. Transcript analyses in patient-derived fibroblasts showed homozygous patients to produce approximately equal amounts of normally spliced mRNA and mRNA with the abnormal retention of intron 3 and containing a premature stop codon (p.Val183Glyfs*31). The aberrant transcript was shown to undergo nonsense-mediated mRNA decay, and thus resulting in SHOX haploinsufficiency in the homozygous patient. Six healthy relatives who are of normal height are heterozygous for this variant and fibroblasts from a heterozygote for the c.544+5G>C variant produced wild-type transcript amounts comparable to healthy control. The unique situation reported here highlights the fact that the dosage of SHOX determines the clinical phenotype rather than the Mendelian inheritance pattern of SHOX variants. This study extends the molecular and inheritance spectrum of SHOX deficiency disorder and highlights the importance of functional testing of SHOX variants of unknown significance in order to allow appropriate counseling and precision medicine for each family individual.
Assuntos
Nanismo , Osteocondrodisplasias , Humanos , Proteínas de Homeodomínio/genética , Proteína de Homoeobox de Baixa Estatura/genética , Transtornos do Crescimento/genética , Osteocondrodisplasias/genética , Osteocondrodisplasias/complicações , Nanismo/genéticaRESUMO
Linear growth during childhood is the result of the synergic contribution of different factors. The best growth determinant system during each period of life is represented by the growth hormone-insulin-like growth factor axis (GH-IGF), even if several other factors are involved in normal growth. Within the broad spectrum of growth disorders, an increased importance has been placed on growth hormone insensitivity (GHI). GHI was reported for the first time by Laron as a syndrome characterized by short stature due to GH receptor (GHR) mutation. To date, it is recognized that GHI represents a wide diagnostic category, including a broad spectrum of defects. The peculiar characteristic of GHI is the low IGF-1 levels associated with normal or elevated GH levels and the lack of IGF-1 response after GH administration. Recombinant IGF-1 preparations may be used in the treatment of these patients.
Assuntos
Nanismo , Hormônio do Crescimento Humano , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Hormônio do Crescimento , Hormônio do Crescimento Humano/metabolismo , Nanismo/tratamento farmacológico , Transtornos do Crescimento/genéticaRESUMO
OBJECTIVE: To analyze the genetic etiology of a Chinese pedigree affected with short stature. METHODS: A child with familial short stature (FSS) who had presented at the Ningbo Women and Children's Hospital in July 2020 and his parents and paternal and maternal grandparents were selected as the study subject. Clinical data of the pedigree was collected, and the proband was subjected to routine growth and development assessment. Peripheral blood samples were collected. The proband was subjected to whole exome sequencing (WES), and the proband, his parents and grandparents were subjected to chromosomal microarray analysis (CMA). RESULTS: The height of the proband and his father was 87.7cm (-3 s) and 152 cm (-3.39 s) respectively. Both of them were found to harbor a 15q25.3-q26.1 microdeletion, which has encompassed the whole of the ACAN gene which is closely associated with short stature. The CMA results of his mother and grandparents were all negative, and above deletion has not been included in population database and related literature, and was rated as pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). After 14 months of rhGH treatment, the height of the proband has increased to 98.5 cm (-2.07 s). CONCLUSION: The 15q25.3-q26.1 microdeletion probably underlay the FSS, in this pedigree. Short-term rhGH treatment can effectively improve the height of the affected individuals.
Assuntos
Agrecanas , Nanismo , População do Leste Asiático , Criança , Feminino , Humanos , Masculino , Agrecanas/genética , Nanismo/genética , Mutação , LinhagemRESUMO
OBJECTIVE: Growth hormone insensitivity (GHI) encompasses growth restriction, normal/elevated growth hormone (GH), and low insulin-like growth factor I (IGF1). "Nonclassical" GHI is poorly characterized and is rarely caused by heterozygous dominant-negative (DN) variants located in the intracellular or transmembrane domains of the GH receptor (GHR). We sought to determine the molecular mechanisms underpinning the growth restriction in 2 GHI cases. METHODS AND DESIGN: A custom-made genetic investigative pipeline was exploited to identify the genetic cause of growth restriction in patients with GHI. Nanoluc binary technology (NanoBiT), in vitro splicing assays, western blotting, and flow cytometry, characterized the novel GHR variants. RESULTS: Novel heterozygous GHR variants were identified in 2 unrelated patients with GHI. In vitro splicing assays indicated both variants activated the same alternative splice acceptor site resulting in aberrant splicing and exclusion of 26 base pairs of GHR exon 9. The GHR variants produced truncated receptors and impaired GH-induced GHR signaling. NanoBiT complementation and flow cytometry showed increased cell surface expression of variant GHR homo/heterodimers compared to wild-type (WT) homodimers and increased recombinant human GH binding to variant GHR homo/heterodimers and GH binding protein (GHBP) cleaved from the variant GHRs. The findings demonstrated increased variant GHR dimers and GHBP with resultant GH sequestration. CONCLUSION: We identified and characterized 2 novel, naturally occurring truncated GHR gene variants. Intriguingly, these DN GHR variants act via the same cryptic splice acceptor site, highlighting impairing GH binding to excess GHBP as a potential therapeutic approach.
Assuntos
Nanismo , Hormônio do Crescimento Humano , Humanos , Hormônio do Crescimento/genética , Receptores da Somatotropina/genética , Sítios de Splice de RNA , Hormônio do Crescimento Humano/metabolismo , Nanismo/genética , Fator de Crescimento Insulin-Like I/genéticaRESUMO
OBJECTIVES: Laron dwarfism is a rare genetic disorder first reported among Israeli jewish children, subsequently about 350 cases cases have been reported worldwide. We aim to describe the clinical profile of nine children with Laron dwarfism from Institute of Child Health, Chennai. METHODS: Analysis of case records from 2010 to 2018. RESULTS: Male:female ratio is 6:3. Mean age of the children at the time of diagnosis was 3 years. All children were extremely short, and mean height Z score (SD) was -7.7(0.8). All children had characteristic facies with no hypoglycaemic episodes. Microcephaly was present in four children out of which two had developmental delay. Three out of six boys had micropenis. All children had low insulin like growth factor-1 (IGF-1) and high basal growth hormone (GH) with a mean (SD) of 39.6 (11.2) ng/mL. CONCLUSIONS: Suspicion of Laron syndrome should be high when child presents with features of Growth Hormone Deficiency (GHD) with extreme stunting.
Assuntos
Nanismo Hipofisário , Nanismo , Síndrome de Laron , Criança , Humanos , Masculino , Feminino , Pré-Escolar , Atenção Terciária à Saúde , Índia , Hormônio do Crescimento , Nanismo Hipofisário/diagnóstico , Fator de Crescimento Insulin-Like I , Nanismo/genéticaRESUMO
BACKGROUND: Herbal medicines have been used for a long time to treat idiopathic short stature (ISS) in children in East Asian countries. The aim of this study was to analyze the cost-effectiveness of 5 herbal medicines frequently used in clinical settings for children with ISS based on medical records. METHODS: Patients with ISS who had been prescribed a 60-day supply of herbal medicines in 1 Korean medicine hospital were included in this analysis. Their height and height percentile were measured before and after treatment within 6-months. The average cost-effectiveness ratios (ACERs) of 5 herbal medicines for height (cm) and height percentile were calculated for boys and girls, respectively. RESULTS: The ACERs per 1 cm height growth were USD 56.2 (Naesohwajung-Tang), USD 74.8 (Ogapi-Growth decoction), USD 86.6 (Gamcho-Growth decoction), USD 94.6 (Gwakhyangjeonggi-San plus Yukmijihwang-Tang), and USD 113.8 (Boyang-Growth decoction). The ACERs per 1 percentile height growth were USD 205 (Naesohwajung-Tang), USD 293 (Ogapi-Growth decoction), USD 470 (Gamcho-Growth decoction), USD 949 (Boyang-Growth decoction), and USD 1051 (Gwakhyangjeonggi-San plus Yukmijihwang-Tang). CONCLUSION: Herbal medicine might be a potential economical alternative treatment for ISS.
Assuntos
Nanismo , Hormônio do Crescimento Humano , Plantas Medicinais , Masculino , Feminino , Humanos , Criança , Análise de Custo-Efetividade , Nanismo/tratamento farmacológico , Hormônio do Crescimento Humano/uso terapêutico , Transtornos do Crescimento/tratamento farmacológico , EstaturaRESUMO
Background: Gene expression (GE) data have shown promise as a novel tool to aid in the diagnosis of childhood growth hormone deficiency (GHD) when comparing GHD children to normal children. The aim of this study was to assess the utility of GE data in the diagnosis of GHD in childhood and adolescence using non-GHD short stature children as a control group. Methods: GE data was obtained from patients undergoing growth hormone stimulation testing. Data were taken for the 271 genes whose expression was utilized in our previous study. The synthetic minority oversampling technique was used to balance the dataset and a random forest algorithm applied to predict GHD status. Results: 24 patients were recruited to the study and eight subsequently diagnosed with GHD. There were no significant differences in gender, age, auxology (height SDS, weight SDS, BMI SDS) or biochemistry (IGF-I SDS, IGFBP-3 SDS) between the GHD and non-GHD subjects. A random forest algorithm gave an AUC of 0.97 (95% CI 0.93 - 1.0) for the diagnosis of GHD. Conclusion: This study demonstrates highly accurate diagnosis of childhood GHD using a combination of GE data and random forest analysis.
Assuntos
Nanismo , Hormônio do Crescimento , Transcriptoma , Adolescente , Criança , Humanos , Grupos Controle , Perfilação da Expressão Gênica , Hormônio do Crescimento/deficiênciaRESUMO
The identification of the dwarf phenotype in chicken is based on body weight, height, and shank length, leaving the differentiation between dwarf and small breeds ambiguous. The aims of the present study were to characterize the sequence variations associated with the dwarf phenotype in three Italian chicken breeds and to investigate the genes associated with their phenotype. Five hundred and forty-one chickens from 23 local breeds (from 20 to 24 animals per breed) were sampled. All animals were genotyped with the 600 K chicken SNP array. Three breeds were described as "dwarf", namely, Mericanel della Brianza (MERI), Mugellese (MUG), and Pepoi (PPP). We compared MERI, MUG, and PPP with the four heaviest breeds in the dataset by performing genome-wide association studies. Results showed significant SNPs associated with dwarfism in the MERI and MUG breeds, which shared a candidate genomic region on chromosome 1. Due to this similarity, MERI and MUG were analyzed together as a meta-population, observing significant SNPs in the LEMD3 and HMGA2 genes, which were previously reported as being responsible for dwarfism in different species. In conclusion, MERI and MUG breeds seem to share a genetic basis of dwarfism, which differentiates them from the small PPP breed.
Assuntos
Galinhas , Nanismo , Animais , Galinhas/genética , Estudo de Associação Genômica Ampla , Genômica , Itália , Nanismo/genética , Nanismo/veterináriaRESUMO
Autosomal recessive primary microcephaly type 3 (MCPH3) caused by pathogenic variations in CDK5RAP2, is characterized by sensorineural hearing loss, abnormality of skin pigmentation, ocular defects and severe microcephaly associated with neurodevelopmental delay. In this study, we expand the phenotype of MCPH3 as we describe a 10-year-old girl with a biallelic exonic frameshift variant in CDK5RAP2 displaying previously unreported features usually associated with Meier-Gorlin and microcephalic osteodysplastic primordial dwarfism type II (MOPDII). We further describe the clinical phenotype of this form of centrosomal-based primary microcephaly and emphasize the importance of skeletal defect screening in affected individuals.
Assuntos
Nanismo , Microcefalia , Osteocondrodisplasias , Feminino , Humanos , Microcefalia/patologia , Nanismo/genética , Nanismo/diagnóstico , Osteocondrodisplasias/genética , Osteocondrodisplasias/diagnóstico , Retardo do Crescimento Fetal/genética , Retardo do Crescimento Fetal/diagnóstico , Proteínas do Tecido Nervoso , Proteínas de Ciclo Celular/genéticaRESUMO
Coffin-Siris syndrome (CSS) 6 is caused by heterozygous pathogenic variants in the AT-rich interaction domain 2 (ARID2) gene on 12q12. Currently, only 26 cases with both detailed clinical and genetic information have been documented in the literature. Microdeletions of the entire ARID2 gene are rare. In this study, we report a 5-year-7-month-old Chinese female who underwent whole-exome sequencing to discover that she had a de novo 1.563 Mb heterozygous copy number loss at 12q12q13.11, involving an entire deletion of ARID2. The female had severe short stature with obvious dysmorphic facial features, global developmental delay and hypoplastic fingers and toes. Her growth hormone level was normal, with reduced IGF-1 and increased CA19-9 levels. After a review of the 27 patients with ARID2 deficiency, a significant positive correlation was observed between age and height standard deviation score (SDS) (r = 0.71, p = 0.0002), suggesting a possibility of growth catch-up. This study expands the genetic and phenotypic spectrum of CCS6 and provides a decision-making reference for growth hormone therapy.
Assuntos
Anormalidades Múltiplas , Nanismo , Deformidades Congênitas da Mão , Deficiência Intelectual , Micrognatismo , Feminino , Humanos , Lactente , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Nanismo/genética , Face/patologia , Deformidades Congênitas da Mão/diagnóstico , Deformidades Congênitas da Mão/genética , Deformidades Congênitas da Mão/patologia , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Micrognatismo/diagnóstico , Micrognatismo/genética , Micrognatismo/patologia , Pescoço/patologia , Fatores de Transcrição/genéticaRESUMO
Frizzled 2 (FZD2) is a transmembrane Wnt receptor. We previously identified a pathogenic human FZD2 variant in individuals with FZD2-associated autosomal dominant Robinow syndrome. The variant encoded a protein with a premature stop and loss of 17 amino acids, including a region of the consensus dishevelled-binding sequence. To model this variant, we used zygote microinjection and i-GONAD-based CRISPR/Cas9-mediated genome editing to generate a mouse allelic series. Embryos mosaic for humanized Fzd2W553* knock-in exhibited cleft palate and shortened limbs, consistent with patient phenotypes. We also generated two germline mouse alleles with small deletions: Fzd2D3 and Fzd2D4. Homozygotes for each allele exhibit a highly penetrant cleft palate phenotype, shortened limbs compared with wild type and perinatal lethality. Fzd2D4 craniofacial tissues indicated decreased canonical Wnt signaling. In utero treatment with IIIC3a (a DKK inhibitor) normalized the limb lengths in Fzd2D4 homozygotes. The in vivo replication represents an approach for further investigating the mechanism of FZD2 phenotypes and demonstrates the utility of CRISPR knock-in mice as a tool for investigating the pathogenicity of human genetic variants. We also present evidence for a potential therapeutic intervention.
Assuntos
Fissura Palatina , Nanismo , Deformidades Congênitas dos Membros , Anormalidades Urogenitais , Animais , Humanos , Camundongos , Fissura Palatina/genética , Nanismo/genética , Deformidades Congênitas dos Membros/genética , Anormalidades Urogenitais/genética , Via de Sinalização Wnt/genética , Modelos Animais de Doenças , Receptores Frizzled/genética , Técnicas de Introdução de GenesRESUMO
Since the first report of SOPH syndrome among the Yakut population in 2010, new clinical data of SOPH-like conditions continue to appear. We expand the phenotypic spectrum of SOPH syndrome and perform a comparative analysis of Yakut SOPH patients' clinical data with SOPH-like conditions reported in the world scientific literature to form a foundation for NBAS pathogenesis discussion. Clinical data from the genetic records of 93 patients with SOPH syndrome and global survey data on patients with pathogenic variants of the C-terminal in the NBAS gene were collected. A detailed phenotype description of patients is presented with a total number of 111 individuals. Underweight below the fifth centile and prone to delayed bone age in Yakut SOPH patients are retrospectively observed. We outline the short stature with optic atrophy as the leading phenotyping trait for C-terminal NBAS patients. The pathophysiology and patients management of SOPH-like conditions are discussed.
Assuntos
Nanismo , Atrofia Óptica , Humanos , Estudos Retrospectivos , Proteínas de Neoplasias/genética , Fenótipo , Atrofia Óptica/genética , Nanismo/genéticaRESUMO
BACKGROUND: When treated in a dental chair, patients with deformities such as scoliosis often require special consideration. CASE REPORT: Here is a case of 9 years old Saudi child who was reported with dental problems. The objective of this study is to provide a guideline for dental management of diastrophic dysplasia. CONCLUSIONS: Diastrophic dysplasia is a rare and nonlethal skeletal dysplasia, autosomal inheritance recessive, recognized by the infant's dysmorphic changes at birth. Diastrophic dysplasia is not a common hereditary disorder, however, the characteristic of this condition and guidelines for dental treatment should be known to a pediatric dentist, particularly at a major medical center.
Assuntos
Nanismo , Escoliose , Criança , Lactente , Recém-Nascido , Humanos , Radiografia , Assistência OdontológicaRESUMO
(1) Background: Dyggve-Melchior-Clausen Syndrome is a skeletal dysplasia caused by a defect in the DYM gene (OMIM number 607461). Pathogenic variants in the gene have been reported to cause Dyggve-Melchior-Clausen (DMC; OMIM 223800) dysplasia and Smith-McCort (SMC; OMIM 607326) dysplasia. (2) Methods: In the present study, large consanguineous families with five affected individuals with osteochondrodysplasia phenotypes were recruited. The family members were analyzed by polymerase chain reaction for homozygosity mapping using highly polymorphic microsatellite markers. Subsequent to linkage analysis, the coding exons and exon intron border of the DYM gene were amplified. The amplified products were then sent for Sanger sequencing. The structural effect of the pathogenic variant was analyzed by different bioinformatics tools. (3) Results: Homozygosity mapping revealed a 9 Mb homozygous region on chromosome 18q21.1 harboring DYM shared by all available affected individuals. Sanger sequencing of the coding exons and exon intron borders of the DYM gene revealed a novel homozygous nonsense variant [DYM (NM_017653.6):c.1205T>A, p.(Leu402Ter)] in affected individuals. All the available unaffected individuals were either heterozygous or wild type for the identified variant. The identified mutation results in loss of protein stability and weekend interactions with other proteins making them pathogenic (4) Conclusions: This is the second nonsense mutation reported in a Pakistani population causing DMC. The study presented would be helpful in prenatal screening, genetic counseling, and carrier testing of other members in the Pakistani community.
Assuntos
Nanismo , Deficiência Intelectual , Osteocondrodisplasias , Humanos , Osteocondrodisplasias/genética , Peptídeos e Proteínas de Sinalização Intracelular , Nanismo/genética , Deficiência Intelectual/genéticaRESUMO
OBJECTIVE: To investigate the clinical and genetic characteristics of a patient with STISS syndrome due to variant of PSMD12 gene. METHODS: Clinical data and result of genetic testing of a patient who was admitted to Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine on October 4, 2020 were analyzed, together with a review of relevant literature. RESULTS: The patient was found to harbor a heterozygous c.601C>T (p.Arg201*) nonsense variant of the PSMD12 gene, which was unreported previously. Clinically, the height of the patient has differed significantly from reported in the literature. An extremely rare case of STISS syndrome due to variant of the PSMD12 gene has been diagnosed. CONCLUSION: Whether the severely short stature is part of the clinical spectrum for PSMD12 gene variants needs to be further explored, and the efficacy and safety of growth hormone therapy has yet to be determined.
Assuntos
Nanismo , Criança , Humanos , China , Testes Genéticos , Heterozigoto , SíndromeRESUMO
Sexually antagonistic selection, which favours different optima in males and females, is predicted to play an important role in the evolution of sex chromosomes. Body size is a sexually antagonistic trait in the shell-brooding cichlid fish Lamprologous callipterus, as "bourgeois" males must be large enough to carry empty snail shells to build nests whereas females must be small enough to fit into shells for breeding. In this species, there is also a second male morph: smaller "dwarf" males employ an alternative reproductive strategy by wriggling past spawning females into shells to fertilize eggs. L. callipterus male morphology is passed strictly from father to son, suggesting Y-linkage. However, sex chromosomes had not been previously identified in this species, and the genomic basis of size dimorphism was unknown. Here we used whole-genome sequencing to identify a 2.4-Mb sex-linked region on scaffold_23 with reduced coverage and single nucleotide polymorphism density in both male morphs compared to females. Within this sex region, distinct Y-haplotypes delineate the two male morphs, and candidate genes for body size (GHRHR, a known dwarfism gene) and sex determination (ADCYAP1R1) are in high linkage disequilibrium. Because differences in body size between females and males are under strong selection in L. callipterus, we hypothesize that sexual antagonism over body size initiated early events in sex chromosome evolution, followed by Y divergence to give rise to bourgeois and dwarf male reproductive strategies. Our results are consistent with the hypothesis that sexually antagonistic traits should be linked to young sex chromosomes.