Background

Osteogenesis Imperfecta is a genetic disorder affecting the synthesis of collagen in the body. It is also known as ‘Brittle Bone Disease’. It is heterogenous in its clinical presentation. The commonest presentation is a history of frequent fractures, joint deformities and blue sclera. Secondary deformities of the extremities, spine, skull as well short stature observed frequently.

Hearing loss has been well documented to occur in Osteogenesis Imperfecta. It is most commonly seen in types I, II and III. Hearing loss forms part of the diagnostic criteria for these types. Depending on the study, the prevalence of hearing loss in children with Osteogenesis imperfecta is between 6.7% and 77.3% The estimated prevalence of Osteogenesis Imperfecta is 1 in 20000.

Objectives

In South Africa, the commonest type of Osteogenesis Imperfecta was found to be Type III. The prevalence of OI Type III has been estimated to be between 1:125000 and 1:200000. Hearing loss is a common feature of OI Type III.

Methods

This study was a Prospective Cross-sectional study. Ethics Approval was obtained from the University of Witwatersrand Ethics committee (Ethics number M190975) Children with Osteogenesis Imperfecta attending the Metabolic Bone Clinic at Chris Hani Baragwanath Academic Hospital were the target group. The patients and their parents or guardians were recruited at the clinic after a consent and or an assent was obtained. An Otoscopy followed by tympanometry and a hearing screen based on the age of the patient was done. DPEOAEs were also done as a screening test to confirm the pure tone audiogram findings. The results were given to the patients and their parents/guardians immediately.

Results

The paediatric patients with Osteogenesis Imperfecta who consented to take part in the study had their hearing screen done at the Audiology Department at Chris Hani Baragwanath Academic Hospital. All of the children were found to have normal hearing. On tympanometry, all except 2 were found to have type A curves in bilaterally. Two patients had a type As curve in one ear with an A curve on the other side.

Conclusion

Hearing loss in Osteogenesis Imperfecta forms part of the diagnostic criteria for certain types of this genetic disorder. Hearing loss in the paediatric patients does not seem to be as prevalent as previously thought. All the patients involved in the study were receiving the bisphosphonate therapy (Zoledronic acid) for OI. This may possibly cause a delay in the onset of hearing loss but long term follow-up studies and bigger sample sizes will be required to prove this hypothesis.

中文翻译：

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成骨不全和儿科人群的听力损失

背景

成骨不全症是一种影响体内胶原蛋白合成的遗传性疾病。它也被称为“脆骨病”。它的临床表现是异质的。最常见的表现是有频繁骨折、关节畸形和蓝色巩膜的病史。经常观察到四肢、脊柱、颅骨的继发性畸形以及身材矮小。

听力损失已被充分证明发生在成骨不全症中。它最常见于 I、II 和 III 型。听力损失是这些类型诊断标准的一部分。根据研究，成骨不全症儿童听力损失的患病率在 6.7% 到 77.3% 之间。成骨不全症的估计患病率为 20000 分之一。

目标

在南非，最常见的成骨不全症是 III 型。OI III 型的患病率估计在 1:125000 和 1:200000 之间。听力损失是 OI III 型的一个共同特征。

方法

这项研究是一项前瞻性横断面研究。获得了威特沃特斯兰德大学伦理委员会的伦理批准（伦理编号 M190975）就诊于 Chris Hani Baragwanath Academic Hospital 代谢骨诊所的成骨不全儿童是目标群体。在获得同意和/或同意后，患者及其父母或监护人被招募到诊所。进行了耳镜检查，随后进行了鼓室压测量，并根据患者的年龄进行了听力筛查。DPEOAE 也作为筛选测试进行，以确认纯音听力图结果。结果立即提供给患者及其父母/监护人。

结果

同意参与该研究的成骨不全儿科患者在 Chris Hani Baragwanath Academic Hospital 的听力科进行了听力筛查。所有的孩子都被发现有正常的听力。在鼓室压测量中，除 2 例外，均发现双侧 A 型曲线。两名患者的一只耳朵呈 A 型曲线，另一侧呈 A 型曲线。

结论

成骨不全症的听力损失构成了这种遗传疾病某些类型的诊断标准的一部分。儿科患者的听力损失似乎并不像以前认为的那样普遍。参与研究的所有患者均接受双膦酸盐治疗（唑来膦酸）治疗 OI。这可能会导致听力损失发生的延迟，但需要长期的后续研究和更大的样本量来证明这一假设。