Mild phenotypes in patients with different deletions in the 3' enhancer region of SHOX.

Haploinsufficiency of the short stature homeobox-containing (SHOX) gene leads to a phenotypic spectrum ranging from Leri-Weill dyschondrosteosis (LWD) to SHOX-deficient short stature. SHOX nullizygosity leads to Langer mesomelic dysplasia. Pathogenic variants can include whole or partial gene deletions or duplications, point mutations within the coding sequence, and deletions of upstream and downstream regulatory elements. Here we report two families: a non-consanguineous family with a deletion downstream of SHOX, in which the homozygous proband presented with isolated Madelung deformity, without LWD or short stature, as well as a 9-year-old girl with Madelung deformities, mesomelia, a dominant family history of Madelung deformity and a heterozygous deletion of the CNE9 region in the 3' downstream region of SHOX. These case reports provide additional information on the effects of 3' downstream deletions of SHOX, by demonstrating the limited phenotype associated with the recurrent 47.5 kb deletion in a homozygous state and the CNE9 deletion in a heterozygous state.

Caracterización clínica de pacientes chilenos con displasia fibrosa/síndrome de McCune-Albright / Clinical features of Chilean patients with Fibrous Dysplasia/McCune-Albright Syndrome

BACKGROUND: Fibrous Dysplasia/McCune-Albright Syndrome (FD/MAS) is characterized by a spectrum of manifestations that may include fibrous dysplasia of bone and multiple endocrinopathies. AIM: To describe the clinical spectrum, the study and follow-up of patients with FD/MAS cared at our institution. MATERIAL AND METHODS: Review of medical records of 12 pediatric and adult patients (11 women) who met the clinical and genetic diagnostic criteria for FD/ MAS. RESULTS: The patients' mean age at diagnosis was 4.9 ± 5.5 years. The most common initial clinical manifestation was peripheral precocious puberty (PPP) in 67% of patients and 75% had café-au-lait spots. Fibrous dysplasia was present in 75% of patients and the mean age at diagnosis was 7.9 ± 4.7 years. Ten patients had a bone scintigraphy, with an age at the first examination that varied between 2 and 38 years of age. The most frequent location of dysplasia was craniofacial and appendicular. No patient had a recorded history of cholestasis, hepatitis, or pancreatitis. In four patients, a genetic study was performed that was positive for the pathogenic variant of guanine nucleotide binding protein, alpha stimulating (GNAS). CONCLUSIONS: These patients demonstrate the variable nature of the clinical presentation and study of FD/MAS. It is essential to increase the index of diagnostic suspicion and adherence to international recommendations.

[Clinical features of Chilean patients with Fibrous Dysplasia/McCune-Albright Syndrome]. / Caracterización clínica de pacientes chilenos con displasia fibrosa/síndrome de McCune-Albright.

BACKGROUND: Fibrous Dysplasia/McCune-Albright Syndrome (FD/MAS) is characterized by a spectrum of manifestations that may include fibrous dysplasia of bone and multiple endocrinopathies. AIM: To describe the clinical spectrum, the study and follow-up of patients with FD/MAS cared at our institution. MATERIAL AND METHODS: Review of medical records of 12 pediatric and adult patients (11 women) who met the clinical and genetic diagnostic criteria for FD/ MAS. RESULTS: The patients' mean age at diagnosis was 4.9 ± 5.5 years. The most common initial clinical manifestation was peripheral precocious puberty (PPP) in 67% of patients and 75% had café-au-lait spots. Fibrous dysplasia was present in 75% of patients and the mean age at diagnosis was 7.9 ± 4.7 years. Ten patients had a bone scintigraphy, with an age at the first examination that varied between 2 and 38 years of age. The most frequent location of dysplasia was craniofacial and appendicular. No patient had a recorded history of cholestasis, hepatitis, or pancreatitis. In four patients, a genetic study was performed that was positive for the pathogenic variant of guanine nucleotide binding protein, alpha stimulating (GNAS). CONCLUSIONS: These patients demonstrate the variable nature of the clinical presentation and study of FD/MAS. It is essential to increase the index of diagnostic suspicion and adherence to international recommendations.

Fetal Genotype-Phenotype Sex Discordance: A Case of 5-Alpha-Reductase Deficiency.

OBJECTIVE: To describe the prenatal and postnatal diagnostic workup leading to the diagnosis of 5-alpha-reductase type 2 deficiency (5AR2D) in a case of 46,XY disorder of sex development (DSD). CASE REPORT: A first-trimester noninvasive prenatal test (NIPT) on maternal blood revealed a male fetus with a low risk of aneuploidy. However, a female fetus was identified at the second-trimester scan. A repeat sample revealed similar results and ruled out the possibility of both a sample swap or a vanishing twin. At birth, phenotypically female external genitalia were evident, with testes noted in the labioscrotal area. Neonatal blood confirmed a 46,XY complement and a 46,XY DSD genetic panel revealed a 5AR2D. CONCLUSION: Our case and others described in the literature demonstrate that fetal sex discordance detected by a combination of NIPT and subsequent ultrasound examination can be associated with several biological conditions, with DSD being the most significant.

Observed Frequency and Characteristics of Hearing Loss in Osteogenesis Imperfecta

ABSTRACT Background: Osteogenesis imperfecta (OI) is a rare group of genetic disorders affecting connective tissue, with consequent bone fragility, frequent fractures and skeletal deformity. Depending on the type, patients can have blue sclera, dentinogenesis imperfecta, and hearing loss. Aim: To determine the frequency, type and audiometric characteristics of hearing loss in a group of patients with OI. Material and Methods: A prospective cohort study was completed. A clinical and diagnostic hearing evaluation with tympanometry, acoustic stapedial reflex, pure-tone and speech audiometry were performed. Results: Thirty patients completed the study; mean age of 22 years (range 6-63 years). Sixty seven percent had a type I OI. Overall, nine (30%) patients had hearing loss (15/60 ears). Of these, six had bilateral hearing loss. Of the 15 affected ears, six showed conductive hearing loss, five sensorineural hearing loss, and four mixed hearing loss. Patients with hearing loss were older than patients with normal hearing. Only one pediatric patient developed hearing loss. Of the ears without hearing loss, 13% did not have an acoustic stapedial reflex. Conclusions: In this group of patients with OI, 30% had hearing loss and among those ears with normal hearing, 13% did not have an acoustic stapedial reflex. Patients with OI should be monitored for hearing loss.

Antecedentes: La osteogénesis imperfecta (OI) es un grupo raro de trastornos genéticos que afectan al tejido conectivo, con la consiguiente fragilidad ósea, fracturas frecuentes y deformidad esquelética. Según el tipo, los pacientes pueden presentar escleras azules, dentinogénesis imperfecta e hipoacusia. Objetivos: Determinar la frecuencia, tipo y características audiométricas de la hipoacusia en un grupo de pacientes con OI. Material y Métodos: Se completó un estudio de cohorte prospectivo. Se realizó una evaluación clínica, y de la audición con timpanometría, reflejo estapedial, audiometría tonal y logoaudiometría. Resultados: Treinta pacientes completaron el estudio; edad media de 22 años (rango 6-63 años). El 67% tenía una OI tipo I. Nueve pacientes (30%) tuvieron hipoacusia (15/60 oídos). De estos, seis tenían hipoacusia bilateral. De los 15 oídos afectados, seis tenían hipoacusia de conducción, cinco hipoacusia neurosensorial y cuatro hipoacusia mixta. Los pacientes con hipoacusia eran mayores que los pacientes con audición conservada. Sólo un paciente pediátrico desarrolló hipoacusia. De los oídos sin hipoacusia, el 13% tenía un reflejo estapedial ausente. Conclusiones: En este grupo de pacientes con OI, el 30% tenía hipoacusia. Además, el 13% de los oídos con audición normal no tenía reflejo acústico estapedial. Los pacientes con OI deben ser monitoreados para detectar hipoacusia.

Assessment of longitudinal bone growth in osteogenesis imperfecta using metacarpophalangeal pattern profiles.

OBJECTIVE: Osteogenesis imperfecta (OI) is commonly associated with short stature, but it is unclear whether this is exclusively secondary to fractures and bone deformities or whether there is a primary defect in longitudinal bone growth. As metacarpal and phalangeal bones are rarely affected by fractures and deformities, any length deficits in these bones should reflect a direct disease effect on longitudinal growth. This study therefore assessed the relationship of hand bone length with clinical OI type and genotype. STUDY DESIGN: Prospective study. RESULTS: The length of all 19 tubular hand bones were measured in 144 individuals (age 6 to 57 years; 68 female) who had OI caused by COL1A1 or COL1A2 variants. Measurements of bone length were converted to z-scores using published reference data. Bone length was mostly normal in OI type I but was significantly decreased in OI types III and IV. Mean hand bone length z-score (i.e., the average length z-score of all 19 bones of a hand) was -0.2 for OI type I, -2.9 for OI type III and -1.2 for OI type IV. Mean hand bone length z-score was positively associated with height z-score (r2 = 0.65, P < 0.001). Regarding genotype-phenotype correlations, mean hand bone length z-score was close to 0 in individuals with COL1A1 mutations leading to haploinsufficiency but were significantly lower in the presence of mutations leading to triple-helical glycine substitutions in either the alpha 1 or alpha 2 chain of collagen type I. CONCLUSION: COL1A1 and COL1A2 mutations affect bone growth not only by inducing fractures and bone deformities, but also through longitudinal growth deficits in bones that do not fracture or deform.

Observed Frequency and Characteristics of Hearing Loss in Osteogenesis Imperfecta.

BACKGROUND: Osteogenesis imperfecta (OI) is a rare group of genetic disorders affecting connective tissue, with consequent bone fragility, frequent fractures and skeletal deformity. Depending on the type, patients can have blue sclera, dentinogenesis imperfecta, and hearing loss. AIM: To determine the frequency, type and audiometric characteristics of hearing loss in a group of patients with OI. MATERIAL AND METHODS: A prospective cohort study was completed. A clinical and diagnostic hearing evaluation with tympanometry, acoustic stapedial reflex, pure-tone and speech audiometry were performed. RESULTS: Thirty patients completed the study; mean age of 22 years (range 6-63 years). Sixty seven percent had a type I OI. Overall, nine (30%) patients had hearing loss (15/60 ears). Of these, six had bilateral hearing loss. Of the 15 affected ears, six showed conductive hearing loss, five sensorineural hearing loss, and four mixed hearing loss. Patients with hearing loss were older than patients with normal hearing. Only one pediatric patient developed hearing loss. Of the ears without hearing loss, 13% did not have an acoustic stapedial reflex. CONCLUSIONS: In this group of patients with OI, 30% had hearing loss and among those ears with normal hearing, 13% did not have an acoustic stapedial reflex. Patients with OI should be monitored for hearing loss.