Pronounced short stature in a girl with tricho-rhino-phalangeal syndrome II (TRPS II, Langer-Giedion syndrome) and growth hormone deficiency

Minimal Critical Region and Genes for a Typical Presentation of Langer-Giedion Syndrome

Langer-Giedion syndrome (LGS) is caused by a contiguous deletion at 8q23q24, characterized by exostoses, facial, ectodermal, and skeletal anomalies, and, occasionally, intellectual disability. LGS patients have been diagnosed clinically or by routine cytogenetic techniques, hampering the definition of an accurate genotype-phenotype correlation for the syndrome. We report two unrelated patients with 8q23q24 deletions, characterized by cytogenomic techniques, with one of them, to our knowledge, carrying the smallest deletion reported in classic LGS cases. We assessed the pathogenicity of the deletion of genes within the 8q23q24 region and reviewed other molecularly confirmed cases from the literature. Our findings suggest a 3.2-Mb critical region for a typical presentation of the syndrome, emphasizing the contribution of the TRPS1, RAD21, and EXT1 genes' haploinsufficiency, and facial dysmorphisms as well as bone anomalies as the most frequent features among patients with LGS. We also suggest a possible role for the CSMD3 gene, whose deletion seems to contribute to central nervous system anomalies. Since studies performing such correlation for LGS patients are limited, our data contribute to improving the ge-notype-phenotype characterization for LGS patients.

An early diagnosis of trichorhinophalangeal syndrome type 1: a case report and a review of literature

Background

Trichorhinophalangeal syndrome (TRPS) is a rare autosomal dominant disorder caused by defects involving the TRPS1 gene. It exhibits distinctive craniofacial, ectodermal and skeletal abnormalities, such as sparse hair, bulbous nasal tip and short deformed fingers, with extremely variable expressivity.

Case presentation

We report the case of a 17 months old girl, who presented growth retardation and dysmorphic features. Postnatal growth was always below − 2 Standard Deviation for both weight and length and physical examination revealed relative macrocephaly, sparse hair, bulbous nasal tip, thin upper lip, protruding ears, prominent forehead, small jaw, and short hands and feet. Patient’s mother shared the same facial features, and presented sparse hair and small hands. The maternal grandfather and two uncles presented short stature, bulbous nasal tip, thin hair, and premature alopecia. Molecular analysis of TRPS1 gene showed a heterozygous c.2086C > T;(p.Arg696Ter) mutation both in the patient and her mother, confirming the diagnosis of TRPS, type I.

Conclusions

Clinical phenotype of TRPS can be subtle and the syndrome often remains undiagnosed. A comprehensive clinical examination and an exhaustive family history are crucial to reach the correct diagnosis, which is essential to perform adequate follow-up and timely therapeutic procedures.

Analysis of porcine body size variation using re-sequencing data of miniature and large pigs

Background

Domestication has led to substantial phenotypic and genetic variation in domestic animals. In pigs, the size of so called minipigs differs by one order of magnitude compared to breeds of large body size. We used biallelic SNPs identified from re-sequencing data to compare various publicly available wild and domestic populations against two minipig breeds to gain better understanding of the genetic background of the extensive body size variation. We combined two complementary measures, expected heterozygosity and the composite likelihood ratio test implemented in “SweepFinder”, to identify signatures of selection in Minipigs. We intersected these sweep regions with a measure of differentiation, namely F_ST, to remove regions of low variation across pigs. An extraordinary large sweep between 52 and 61 Mb on chromosome X was separately analyzed based on SNP-array data of F₂ individuals from a cross of Goettingen Minipigs and large pigs.

Results

Selective sweep analysis identified putative sweep regions for growth and subsequent gene annotation provided a comprehensive set of putative candidate genes. A long swept haplotype on chromosome X, descending from the Goettingen Minipig founders was associated with a reduction of adult body length by 3% in F₂ cross-breds.

Conclusion

The resulting set of genes in putative sweep regions implies that the genetic background of body size variation in pigs is polygenic rather than mono- or oligogenic. Identified genes suggest alterations in metabolic functions and a possible insulin resistance to contribute to miniaturization. A size QTL located within the sweep on chromosome X, with an estimated effect of 3% on body length, is comparable to the largest known in pigs or other species. The androgen receptor AR, previously known to influence pig performance and carcass traits, is the most obvious potential candidate gene within this region.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5009-y) contains supplementary material, which is available to authorized users.

What to consider when pseudohypoparathyroidism is ruled out: iPPSD and differential diagnosis

BACKGROUND

Pseudohypoparathyroidism (PHP) is a rare disease whose phenotypic features are rather difficult to identify in some cases. Thus, although these patients may present with the Albright's hereditary osteodystrophy (AHO) phenotype, which is characterized by small stature, obesity with a rounded face, subcutaneous ossifications, mental retardation and brachydactyly, its manifestations are somewhat variable. Indeed, some of them present with a complete phenotype, whereas others show only subtle manifestations. In addition, the features of the AHO phenotype are not specific to it and a similar phenotype is also commonly observed in other syndromes. Brachydactyly type E (BDE) is the most specific and objective feature of the AHO phenotype, and several genes have been associated with syndromic BDE in the past few years. Moreover, these syndromes have a skeletal and endocrinological phenotype that overlaps with AHO/PHP. In light of the above, we have developed an algorithm to aid in genetic testing of patients with clinical features of AHO but with no causative molecular defect at the GNAS locus. Starting with the feature of brachydactyly, this algorithm allows the differential diagnosis to be broadened and, with the addition of other clinical features, can guide genetic testing.

METHODS

We reviewed our series of patients (n = 23) with a clinical diagnosis of AHO and with brachydactyly type E or similar pattern, who were negative for GNAS anomalies, and classify them according to the diagnosis algorithm to finally propose and analyse the most probable gene(s) in each case.

RESULTS

A review of the clinical data for our series of patients, and subsequent analysis of the candidate gene(s), allowed detection of the underlying molecular defect in 12 out of 23 patients: five patients harboured a mutation in PRKAR1A, one in PDE4D, four in TRPS1 and two in PTHLH.

CONCLUSIONS

This study confirmed that the screening of other genes implicated in syndromes with BDE and AHO or a similar phenotype is very helpful for establishing a correct genetic diagnosis for those patients who have been misdiagnosed with "AHO-like phenotype" with an unknown genetic cause, and also for better describing the characteristic and differential features of these less common syndromes.

Annular pancreas in Trichorhinophalangeal syndrome type II with 8q23.3-q24.12 interstitial deletion

Background

Trichorhinophalangeal syndrome type II (TRPS II, OMIM # 150230) is a rare autosomal dominant genetic disorder characterized by craniofacial and skeletal abnormalities. Loss of functional copies of the TRPS1 gene at 8q23.3 and the EXT1 gene at 8q24.11 are considered to be responsible for the syndrome.

Case Presentation

Herewith, we report an 8-year-old girl with sparse scalp hair, bulbous nose, thin upper lip, broad eyebrows, phalangeal abnormalities of both hands/toes, multiple exostoses, mild intellectual impairment and severe malnutrition. In addition, the patient also had annular pancreas, a rare co-existing feature in patients with TRPS II.

Conclusions

A contiguous 5.47 Mb deletion involving 8q23.3-q24.12 was detected by array comparative genomic hybridization (aCGH), leading to haploinsufficiency of 10 protein coding genes, 1 long non-coding RNA and 1 microRNA. Quantitative PCR (qPCR) examination confirmed half-reduced DNA copy of the patient and normal expression of both parents, indicating a de novo origin of the deletion and complete penetrance of the mutation.

An interstitial deletion at 8q23.1-q24.12 associated with Langer-Giedion syndrome/ Trichorhinophalangeal syndrome (TRPS) type II and Cornelia de Lange syndrome 4

Background

There are three distinct subtypes of Trichorhinophalangeal syndrome (TRPS); TRPS type I, TRPS type II and TRPS type III. Features common to all three subtypes include sparse, slowly growing scalp hair, laterally sparse eyebrows, a bulbous tip of the nose (pear-shaped), and protruding ears. Langer–Giedion syndrome (LGS) or TRPS type II is a contiguous gene syndrome on 8q24.1, involving loss of functional copies of the TRPS1 and EXT1 genes. We report a male patient that was referred to the Department of Medical Genetics due to hypotonia and dysmorphic facial features.

Results

Cytogenetic and array- Comparative Genomic Hybridization (aCGH) analysis revealed that the patient was a carrier of an interstitial deletion at 8q23.1-q24.12 of 12,5 Mb. Parental karyotype indicated that the father carried an apparently balanced insertion: 46, ΧΥ, der(10)ins(10;8)(q22;q23q24).

Conclusions

This is the first report of an apparently balanced insertion including chromosomes 8 and 10 contributing to the etiology of LGS/ TRPS type II. Τimely diagnosis of parental balanced chromosomal rearrangements can reduce the risk of subsequent miscarriages as well as abnormal offspring.

Tricho-rhino-phalangeal syndrome in a 13-year-old girl with chronic renal failure and severe growth retardation

INTRODUCTION

The tricho-rhino-phalangeal syndrome type III (TRPS III) is a rare autosomal dominantly inherited condition. The main clinical features are sparse and slow-growing hair and nails, a pear-shaped nose with a bulbous tip, elongated and flat philtrum, thin upper lip, cone-shaped epiphyses of the phalanges, and short stature. All patients have a point mutation in the TRPS1 gene.

CASE REPORT

In this paper, we present a 13-year-old female with the typical clinical features of TRPS III, extreme growth retardation, severe deformities of both proximal radii resulting in limited extension of the elbows, and chronic renal failure (CRF) in addition. Molecular diagnostics revealed a missense mutation in exon 6 of TRPS1 that she inherited from her father who is also affected with TRPS III, but does not have CRF. In the index patient, the CRF was found to be due to bilateral renal hypodysplasia (RHD).

CONCLUSION

Beside the renal dysplasia, the girl had severe deformities of the proximal radii - findings which have not been reported so far in TRPS III.

Complex chromosomal rearrangements causing Langer-Giedion syndrome atypical phenotype: genotype-phenotype correlation and literature review

Langer-Giedion syndrome (LGS) is caused by a deletion of chromosome 8q23.3-q24.11. The LGS clinical spectrum includes intellectual disability (ID), short stature, microcephaly, facial dysmorphisms, exostoses. We describe a 4-year-old girl with ID, short stature, microcephaly, distinctive facial phenotype, skeletal signs (exostoses on the left fibula, coccyx agenesis, stubby and dysmorphic sphenoid bone, osteoporosis), central nervous system malformations (hypoplastic and dysmorphic corpus callosum and septum pellucidum), pituitary gland hypoplasia and hyperreninemia. Array-CGH revealed complex chromosomal rearrangements. A diagnosis of LGS was confirmed by the detection of a 8q23.3-q24.1 deletion. Associated chromosomal abnormalities were a 21q22.1 deletion and a balanced reciprocal translocation t(2;11)(p24;p15) de novo, confirmed by FISH analysis. We document the patient's atypical findings, never described in LGS patients, in order to update the genotype-phenotype correlation. We speculate that the disruption of regulatory elements mapping upstream CYP11B2 involved in the deleted region could cause hyperreninemia.

Brachydactyly E: isolated or as a feature of a syndrome

Brachydactyly (BD) refers to the shortening of the hands, feet or both. There are different types of BD; among them, type E (BDE) is a rare type that can present as an isolated feature or as part of more complex syndromes, such as: pseudohypopthyroidism (PHP), hypertension with BD or Bilginturan BD (HTNB), BD with mental retardation (BDMR) or BDE with short stature, PTHLH type. Each syndrome has characteristic patterns of skeletal involvement. However, brachydactyly is not a constant feature and shows a high degree of phenotypic variability. In addition, there are other syndromes that can be misdiagnosed as brachydactyly type E, some of which will also be discussed. The objective of this review is to describe some of the syndromes in which BDE is present, focusing on clinical, biochemical and genetic characteristics as features of differential diagnoses, with the aim of establishing an algorithm for their differential diagnosis. As in our experience many of these patients are recruited at Endocrinology and/or Pediatric Endocrinology Services due to their short stature, we have focused the algorithm in those steps that could mainly help these professionals.

Long-term follow-up of four patients with Langer-Giedion syndrome: clinical course and complications

Long-term observations of individuals with the so-called Langer-Giedion (LGS) or tricho-rhino-phalangeal type II (TRPS2) are scarce. We report here a on follow-up of four LGS individuals, including one first described by Andres Giedion in 1969, and review the sparse publications on adults with this syndrome which comprises ectodermal dysplasia, multiple cone-shaped epiphyses prior to puberty, multiple cartilaginous exostoses, and mostly mild intellectual impairment. LGS is caused by deletion of the chromosomal segment 8q24.11-q24.13 containing among others the genes EXT1 and TRPS1. Most patients with TRPS2 are only borderline or mildly cognitively delayed, and few are of normal intelligence. Their practical skills are better than their intellectual capability, and, for this reason and because of their low self-esteem, they are often underestimated. Some patients develop seizures at variable age. Osteomas on processes of cervical vertebrae may cause pressure on cervical nerves or dissection of cerebral arteries. Joint stiffness is observed during childhood and changes later to joint laxity causing instability and proneness to trauma. Perthes disease is not rare. Almost all males become bald at or soon after puberty, and some develop (pseudo) gynecomastia. Growth hormone deficiency was found in a few patients, TSH deficiency so far only in one. Puberty and fertility are diminished, and no instance of transmission of the deletion from a non-mosaic parent to a child has been observed so far. Several affected females had vaginal atresia with consequent hydrometrocolpos.

Third case of 8q23.3-q24.13 deletion in a patient with Langer-Giedion syndrome phenotype without TRPS1 gene deletion

Langer-Giedion syndrome (LGS) is a contiguous gene syndrome caused by a hemizygous deletion on chromosome 8q23.3-q24.11 involving TRPS1 and EXT1 genes. We report on a girl with LGS phenotype and a 7.5 Mb interstitial deletion at chromosome 8q23.3-q24.13. Array-comparative genomic hybridization (a-CGH) revealed a deletion encompassing only the EXT1 and not the TRPS1 gene. Even though the deletion of TRPS1 and EXT1 genes is responsible for craniofacial and skeletal features of LGS, there have been previous reports of patients with LGS phenotype and 8q24 deletions leaving the TRPS1 gene intact. To our knowledge, this is the third such case. Our patient differs from previously reported LGS patients without TRPS1 gene deletion in that she has the typical LGS facial dysmorphism and skeletal abnormalities. However, the girl is of normal height and has only a mild developmental delay. Additionally, she has dyslalia and premature adrenarche classified as Tanner stage 3 premature pubarche which have not yet been described as features of LGS. We examine the molecular breakpoints and phenotypes of our patient and previously reported cases.

Clinical and molecular characterization of a patient with Langer-Giedion syndrome and mosaic del(8)(q22.3q24.13)

The tricho-rhino-phalangeal syndrome type II (TRPS II) is characterized by sparse scalp hair, a long nose with a bulbous tip, a long flat philtrum, cone-shaped epiphyses of the phalanges, retarded bone age in infancy and multiple cartilaginous exostoses. All patients have a hemizygous deletion on chromosome 8q23.3-24.11 which spans at least the 2.8 Mb-region from TRPS1 through EXT1. Only patients with deletions that extend beyond this interval tend to have mental retardation. Here we describe a 14.5-year-old girl with mental retardation and TRPS II. Her facial features are only mild, but she has the typical skeletal features including cone-shaped epiphyses at the phalanges, retarded bone age, multiple exostoses and short stature. She is the first patient with TRPS II and a molecularly proven mosaic interstitial deletion in 8q22.3-q24.13. The deletion is one of the largest ever found in TRPS II, and spans 19.79 Mb and 50 genes or loci including TRPS1 and EXT1. The degree of mosaicism is 7% in lymphocytes from peripheral blood and 97% in skin fibroblasts.

A position effect on TRPS1 is associated with Ambras syndrome in humans and the Koala phenotype in mice

Ambras syndrome (AS) is a rare form of congenital hypertrichosis with excessive hair on the shoulders, face and ears. Cytogenetic studies have previously implicated an association with rearrangements of chromosome 8. Here we define an 11.5 Mb candidate interval for AS on chromosome 8q based on cytogenetic breakpoints in three patients. TRPS1, a gene within this interval, was deleted in a patient with an 8q23 chromosomal rearrangement, while its expression was significantly downregulated in another patient with an inversion breakpoint 7.3 Mb downstream of TRPS1. Here, we describe the first potential long-range position effect on the expression of TRPS1. To gain insight into the mechanisms by which Trps1 affects the hair follicle, we performed a detailed analysis of the hair abnormalities in Koa mice, a mouse model of hypertrichosis. We found that the proximal breakpoint of the Koa inversion is located 791 kb upstream of Trps1. Quantitative real-time polymerase chain reaction, in situ hybridization and immunofluorescence analysis revealed that Trps1 expression levels are reduced in Koa mutant mice at the sites of pathology for the phenotype. We determined that the Koa inversion creates a new Sp1 binding site and translocates additional Sp1 binding sites within a highly conserved stretch spanning the proximal breakpoint, providing a potential mechanism for the position effect. Collectively, these results describe a position effect that downregulates TRPS1 expression as the probable cause of hypertrichosis in AS in humans and the Koa phenotype in mice.

Partial growth hormone deficiency and changed bone quality and mass in type I trichorhinophalangeal syndrome

The trichorhinophalangeal syndromes (TRPSs) are syndromes due to haploinsufficiency of genes in the chromosome 8q24.12 region. Type I TRPS is characterized by typical facial features including sparse, brittle and fine hair, bulbous nose, and a long philtrum, as well as skeletal abnormalities. Growth retardation is a feature frequently found in these patients, who commonly are of short stature; however, only one case with growth hormone deficiency has been described in a TRPS patient and that patient had type II TRPS. Skeletal morphological abnormalities have been studied, but investigation of bone metabolism and quality in this kind of patients are not available. In this report we describe two cases of type I TRPS with partial growth hormone deficiency and significant bone mass and quality impairment, which was unresponsive to GH treatment.