SUDANESE JOURNAL OF PAEDIATRICS

2023; Vol 23, Issue No. 2

IMAGE

Nail-patella syndrome

Zakaria Barsoum (1)

(1) Consultant Paediatrician, Paediatric Department, South West Acute Hospital, Enniskillen, UK

Correspondence to:

Zakaria Barsoum

Consultant Paediatrician, Paediatric Department, South West Acute Hospital, Enniskillen, UK.

Email: doctorzakaria [at] yahoo.com

Received: 14 July 2022 | Accepted: 23 November 2022

How to cite this article:

Barsoum Z. Nail-patella syndrome. Sudan J Paediatr. 2023;23(2):252–254.

https://doi.org/10.24911/SJP.106-1657814963

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The father of this 11-year-old girl has the same disease. The pelvic X-ray of the child (Figure 1) demonstrates a pathognomonic feature of the underlying disease.

1. Which part of the body needs to be examined?

2. What is the most likely diagnosis?

Presentation and main clinical features

NPS is a rare genetic autosomal dominant disorder, characterised by hypoplastic nails and patellae, and the presence of a bilateral extra piece of iliac bones on both sides ‘iliac horns’ in pelvic X-ray [1–4]. The image in our case (Figure 1) clearly shows ‘posterior horns’ of both iliac bones where the posterior aspects of both iliac bones are not even or straight, they are curved and appear like ‘horns’ (Figure 1, arrows), the presence of which is pathognomonic of this rare disorder [1–4]. The child had other features of the disease such as scoliosis and hypoplastic thumb nails. Both patellae were mildly hypoplastic and the right patella was displaced laterally (genu varum) (Figure 2, arrows).

Figure 1. A pathognomonic feature of the underlying disease (see below).

Figure 2. X-ray of both knees. Both patellae were mildly hypoplastic and the right patella was displaced laterally (genu varum).

Other features were absent such as radius dislocation, webbing of skin at the bend of the elbows, and mandibular cysts. Bilateral mild intermittent knee pain was the only symptom and did not interfere with the range of joint movements or daily activities. Ischiopatellar dysplasia or small patella syndrome is an important differential diagnosis [5]. Patients with ischiopatellar dysplasia do not have nail abnormalities, no eye or renal involvement was noted. Ophthalmology and renal follow up are recommended in all children with NPS for the possibility of glaucoma and/or nephropathy in some children [1].

Diagnosis can be confirmed by molecular genetics with a fault in the LXMB1 gene (locus on chromosome 9) in the majority of cases [1–4], and in our case, molecular genetic testing has confirmed that the child is heterozygous for the familial likely pathogenic LMX1B variant c.757>A.

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CONFLICTS OF INTEREST

Nothing to declare.

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FUNDING

None.

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ETHICS APPROVAL

Signed informed consent for publication of medical details has been obtained from the carers of the child. Confidentiality was ensured at all stages. The author declares that ethics approval was not required for this report.

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REFERENCES

1. Sweeney E, Hoover-Fong J, McIntosh I. Nail-patella syndrome. GeneReviews. 2014 Seattle, WA: University of Washington; 1993-2023. [cited 2022 Jun 20]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK1132/
2. Tuncbilek N, Karakas HM, Okten OO. Imaging of nail-patella syndrome. Hong Kong Med J. 2005 Apr;11(2):116–8
3. Goshen E, Schwartz A, Zilka LR, Zwas ST. Bilateral accessory iliac horns: pathognomonic findings in nail-patella syndrome. Scintigraphic evidence on bone scan. Clin Nucl Med. 2000 Jun;25(6):476–7. https://doi.org/10.1097/00003072-200006000-00020
4. Sasidharan R, Gupta N, Toteja N, Yadav B. Diagnosing nail-patella syndrome: can it be so simple? BMJ Case Rep. 2021 Mar 10;14(3):e241833. https://doi.org/10.1136/bcr-2021-241833
5. Penhoat-Gahier M, Chaillous B, Cozic C, Andre V, Cormier G. Small patella syndrome. Joint Bone Spine. 2017 May;84(3):377–8. https://doi.org/10.1016/j.jbspin.2016.05.007

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ANSWERS

1. Nails

2. Nail-patella syndrome (NPS).