Minimal clinical findings in a patient with 15qter microdeletion syndrome: Delineation of the associated phenotype

Teprotumumab and the Evolving Therapeutic Landscape in Thyroid Eye Disease

CONTEXT

Thyroid eye disease (TED) is a sight-threatening and debilitating autoimmune condition, with limited therapies available, that often poses diagnostic and therapeutic challenges. In recent years, the treatment landscape has shifted to early intervention with targeted therapy.

METHODS

A PubMed review of the literature was conducted for the period between 1979 and 2021. Search terms included thyroid eye disease, teprotumumab, targeted therapy, Graves disease, Graves ophthalmopathy, dysthyroid optic neuropathy, and related terms in different combinations. Novel biologic therapies for TED have emerged as alternatives to traditional steroid regimens in recent years. New insights into TED pathophysiology have uncovered the role of the insulin-like growth factor 1 receptor (IGF-1R) and led to the development of teprotumumab, an IGF-1R-inhibiting monoclonal antibody.

RESULTS

Randomized clinical trials demonstrating the efficacy of teprotumumab for TED led to Food and Drug Administration approval. Teprotumumab is gradually replacing immunosuppressive agents as first-line therapy in the United States for active moderate-to-severe TED, while emerging reports also show its use in other stages of the disease. Recent data highlight risk factors for adverse events and screening protocols to maximize patient safety. Personalized therapeutic plans developed through effective partnership between endocrinologists and ophthalmologists aim to enhance the safety and outcomes of TED treatments and improve care for this complex disease.

CONCLUSION

TED management is shifting to an era of targeted therapy with multidisciplinary care. Teprotumumab has demonstrated superior efficacy to conventional treatments and has transformed our therapeutic and surgical algorithms. Clinical guidelines and additional studies are needed to further guide and refine therapy.

Hearing Dysfunction After Treatment With Teprotumumab for Thyroid Eye Disease

PURPOSE

To characterize the frequency, severity, and resolution of hearing dysfunction in patients treated with teprotumumab for thyroid eye disease (TED).

DESIGN

Prospective observational case series.

METHODS

Ophthalmic examination and adverse event assessment, including otologic symptoms, were performed at baseline, after infusions 2, 4, and 8, and at 6-month follow-up in consecutive patients who received at least 4 teprotumumab infusions. Laboratory test results were collected at baseline and during treatment. Audiometry, patulous eustachian tube (PET) testing, and otolaryngology evaluation were obtained for patients with new or worsening otologic symptoms, with a subset obtaining baseline and posttreatment testing.

RESULTS

Twenty-seven patients were analyzed (24 females, 3 males, average 56.3 years old). Twenty-two patients (81.5%) developed new subjective otologic symptoms, after a mean of 3.8 infusions (SD 1.8). At 39.2-week average follow-up after the last infusion, most patients with tinnitus (100%), ear plugging/fullness (90.9%), and autophony (83.3%) experienced symptom resolution, whereas only 45.5% (5 of 11) of patients with subjective hearing loss/decreased word comprehension experienced resolution. Six patients underwent baseline and posttreatment audiometry, 5 of whom developed teprotumumab-related sensorineural hearing loss (SNHL) and 1 patient also developed PET. Three of the 5 patients with teprotumumab-related SNHL had persistent subjective hearing loss at last follow-up. A prior history of hearing loss was discovered as a risk factor for teprotumumab-related SNHL (P = .008).

CONCLUSIONS

Hearing loss is a concerning adverse event of teprotumumab, and its mechanism and reversibility should be further studied. Until risk factors for hearing loss are better understood, we recommend baseline audiometry with PET testing and repeat testing if new otologic symptoms develop. Screening, monitoring, and prevention guidelines are needed.

Case of 15q26-qter deletion associated with a Prader-Willi phenotype

Prader-Willi syndrome (PWS) is one of the common neurogenetic disorders associated with intellectual disability. PWS involves a complex inheritance pattern and is caused by an absence of gene expression on the paternally inherited 15q11.2-q13 region, either due to deletion, maternal uniparental disomy or imprinting defect. The syndrome is characterized principally by severe neonatal hypotonia, a weak suck in infancy that is later followed by hyperphagia and obesity, developmental delay, intellectual disability and short stature. In the case of the chromosome 15q26-qter deletion syndrome or Drayer's syndrome, very few reports have been published. Its characteristics include intrauterine growth restriction, postnatal growth failure, varying degrees of intellectual disability, developmental delay, typical facial appearance and diaphragmatic hernia. The present paper describes a female patient in whom clinical findings were suggestive of PWS and deletion in the 15q26-qter region. Both karyotyping and methylation-specific polymerase chain reaction were shown to be normal. Nevertheless, fluorescence in situ hybridization showed a 15qter deletion that was later mapped by single nucleotide polymorphism (SNP)-array. The deleted genomic region involves the insulin-like growth factor-1 receptor (IGF1R) gene, which is related to short stature, developmental delay and intellectual disability. This case had various clinical characteristics in common with the cases of 15q26-qter deletionand characteristics compatible with PWS.

Phenotypic Features and Response to GH Treatment of Patients With a Molecular Defect of the IGF-1 Receptor

CONTEXT

The phenotype and response to GH treatment of children with an IGF1R defect is insufficiently known.

OBJECTIVE

To develop a clinical score for selecting children with short stature for genetic testing and evaluate the efficacy of treatment.

DESIGN AND SETTING

Case series with an IGF1R defect identified in a university genetic laboratory.

PATIENTS AND INTERVENTIONS

Of all patients with sufficient clinical data, 18 had (likely) pathogenic mutations (group 1) and 7 had 15q deletions including IGF1R (group 2); 19 patients were treated with GH.

MAIN OUTCOME MEASURES

Phenotype and response to GH treatment.

RESULTS

In groups 1 and 2, mean (range) birth weight, length, and head circumference (HC) SD scores (SDSs) were -2.1 (-3.7 to -0.4), -2.7 (-5.0 to -1.0), and -1.6 (-3.0 to 0.0), respectively. At presentation, height, HC, and serum IGF-1 SDSs were -3.0 (-5.5 to -1.7), -2.5 (-4.2 to -0.5), and +1.2 (-1.3 to 3.2), respectively. Feeding problems were reported in 15 of 19 patients. A clinical score with 76% sensitivity is proposed. After 3 years of GH treatment [1.1 (0.2) mg/m2/d] height gain in groups 1 (n = 12) and 2 (n = 7) was 0.9 SDS and 1.3 SDS (at a mean IGF-1 of 3.5 SDS), less than reported for small for gestational age (1.8 SDS).

CONCLUSION

A clinical score encompassing birth weight and/or length, short stature, microcephaly, and IGF-1 is useful for selecting patients for IGF1R analysis. Feeding problems are common and the growth response to GH treatment is moderate.

Bone Status in a Patient with Insulin-Like Growth Factor-1 Receptor Deletion Syndrome: Bone Quality and Structure Evaluation Using Dual-Energy X-Ray Absorptiometry, Peripheral Quantitative Computed Tomography, and Quantitative Ultrasonography

Haploinsufficiency of the insulin-like growth factor (IGF)-1 receptor (IGF1R) gene is a rare, probably under-diagnosed, cause of short stature. However, the effects of IGF1R haploinsufficiency on glucose metabolism, bone status, and metabolism have rarely been investigated. We report the case of a patient referred to our center at the age of 18 months for short stature, failure to thrive, and Silver-Russell-like phenotype. Genetic analysis did not show hypomethylation of the 11p15.5 region or uniparental disomy of chromosome 7. Growth hormone (GH) stimulation tests revealed GH deficiency, whereas IGF-1 was 248 ng/mL. r-hGH treatment showed only a slight improvement (from -4.4 to -3.5 SDS). At 10 years of age, the child was re-evaluated: CGH-array identified a heterozygous de novo 4.92 Mb deletion in 15q26.2, including the IGF1R gene. Dual-energy X-ray absorptiometry showed a normal bone mineral density z-score, while peripheral quantitative computed tomography revealed reduced cortical and increased trabecular elements. A phalangeal bone quantitative ultrasonography showed significantly reduced amplitude-dependent speed of sound and bone transmission time values. The changes in bone architecture, quality, and metabolism in heterozygous IGF1R deletion patients, support the hypothesis that IGF-1 can be a key factor in bone modeling and accrual.

A rare non-Robertsonian translocation involving chromosomes 15 and 21

CONTEXT

Robertsonian translocations (RT) are among the most common balanced structural rearrangements in humans and comprise complete chromatin fusion of the long arm of two acrocentric chromosomes. Nevertheless, non-Robertsonian translocation involving these chromosomes is a rare event.

CASE REPORT

We report a de novo unbalanced translocation involving chromosomes 15 and 21. The newborn was the daughter of a 29-year-old mother and a 42-year-old father. The couple was non-consanguineous. Clinical findings led to the diagnosis of Down syndrome (DS) with severe congenital heart defects (persistent arterial duct, and complete atrioventricular septal defect), as well as low birth length and weight (< 5th and < 10th percentile, respectively, based on specific measurement curves for DS). Conventional cytogenetic analysis revealed the karyotype 46,XX,der(15)(15pter → 15q26.2::21q11.2 → 21 qter). The translocation was confirmed by means of fluorescence in situ hybridization. The parents had normal karyotypes.

CONCLUSIONS

Differently from RT, in our case a rare event occurred involving the distal segment of 15q and the proximal segment of 21q. Only two reports of this translocation, involving chromosomes 15 and 21 but different breakpoints, have been described so far. The association between 21q duplication and 15q deletion makes it difficult to separate the effect of each chromosome, but might also be responsible for increasing the growth retardation, as detected in our case. Cytogenetic analysis on DS patients is mandatory not only to confirm the diagnosis, but also to assess the risk of recurrence at genetic counseling, as well as to evaluate the contribution of other chromosome aberrations in the final phenotype.