ESPE Abstracts

Longitudinal growth is driven by endochondral ossification at the growth plate, where chondrocytes undergo a well-organized cellular differentiation process from stem-like progenitors to rapidly-proliferating transit-amplifying cells and to hypertrophic chondrocytes. Numerous recent studies have demonstrated that epigenetic modifications play a crucial role in human development and childhood growth. For example, Brachydactyly mental retardation syndrome (BDMR) is caused by hap...

Background: Nutritional excess of vitamin A, a precursor for retinoic acid (RA), causes premature epiphyseal fusion, craniosynostosis, as well as light-dependent retinopathy. Similarly, homozygous loss-of-function mutations in one of the major RA-metabolizing enzymes CYP26B1 causes advanced bone age, premature epiphyseal fusion, and craniosynostosis. We studied a patient with markedly accelerated skeletal and dental development, retinal scarring, and autism-spectrum disease.</...

Background: Most children with idiopathic short stature (ISS) have a delayed bone age (BA). ISS with advanced BA is far less common. We studied three families with autosomal dominant short stature, unexplained BA acceleration, and premature growth cessation.Objective and hypotheses: To identify the genetic cause of this condition and describe its clinical spectrum.Method: Whole exome sequencing was performed in selected individuals...

Human growth is a complex trait. A considerable number of gene defects have been shown to cause short stature, but there are only few examples of genetic causes of non-syndromic tall stature. Besides rare variants with large effects and common risk alleles with small effect size, oligogenic effects may contribute to this phenotype. Exome sequencing was carried out in a tall male (height 3.5 SDS) and his parents. Filtered damaging variants with high CADD scores were validated b...

Background: Very tall people attract a lot of attention and represent a clinically and genetically heterogenous group of individuals. Identifying the genetic etiology can provide important insights into the molecular mechanisms regulating linear growth.Methods and Results: We studied a three-generation pedigree with several isolated (non-syndromic) tall members by whole exome sequencing; the tallest man had a height of 2...

Background: Sp7, also known as Osterix (Osx), is a zinc-finger transcription factor, essential for osteoblast differentiation and bone formation. While bone formation is absent in Osx knockout mice, human loss of function mutations lead to impaired bone formation and cause recessive osteogenesis imperfecta, type XII (OMIM 613849 ).Case: The 5-year-old son of non-consanguineous parents presented with multiple long bone fr...

NMDA (N-Methyl-D-aspartic acid) receptors have been shown to control the timing of sexual maturation in laboratory animals. Therefore, variants in genes impacting NMDA receptor signaling might be predicted to affect human puberty. We studied an extended family with extremely delayed puberty (menarche at 16.5 - 18 years for female family members and pubertal onset at 16 years for male family members). Exome sequencing revealed a rare missense variant (F900V) in DLG2, w...