Nail-patella syndrome: report of 11 pediatric cases

Congenital nail abnormalities

Congenital nail disorders are an uncommon presenting symptom which can be difficult to diagnose and manage. Nail diseases in the pediatric population differ from those in adults in terms of diagnosis, approach and management. In most cases, they do not require treatment and resolve with growth. Physicians need to be able to recognize them, to reassure the parents. The most frequently encountered pathologies associated with nail disorder are syndactyly, acrosyndactyly, symbrachydactyly, macrodactyly, Wassel I thumb duplication, Kirner's deformity and congenital onychodysplasia of the index finger. Treatment usually consists in surgical correction of the deformity. Nail malformation can also be an aspect of a systemic disease. It may provide a clue for screening, and should not be overlooked. Nail conditions can be the first sign of nail-patella syndrome, ectodermal dysplasia, dyskeratosis congenita, epidermolysis bullosa, pachyonychia congenita or lung disease. Medical treatment is therefore discussed on a case-by-case basis.

Nail changes in children with idiopathic congenital clubfoot deformity

BACKGROUND/OBJECTIVES

Nail alterations are commonly seen in cases of idiopathic clubfoot and may cause parental concern. The nature of and whether these changes are congenital or develop secondary to treatment has been poorly investigated. The aim of this study was to evaluate toenail morphology in clubfoot patients at presentation, to re-evaluate them during the course of treatment for the clubfoot, and to analyze findings in the light of the few literature reports for healthy children of the same age.

METHODS

Thirty infants (21 males and 9 females) with idiopathic clubfoot were prospectively enrolled at the Anna Meyer Children's University Hospital. Nails of affected and non-affected feet were evaluated by a team of pediatric dermatologists at presentation and re-evaluated once per patient during the bracing period of Ponseti treatment.

RESULTS

Toenails of affected (47) and non-affected (13) feet were abnormal at presentation in 43.3% of patients, in both clubfeet (40.4%) and non-affected feet (38.5%), but most changes were physiologic or transitory alterations, commonly found in healthy children, with nail concavity (koilonychia) being the most common finding (29.7%). Changes were not related to clubfoot severity or laterality (P > .05). In most (76.9%) unilateral cases, there was concordance of nail changes between clubfoot and non-affected foot. At re-evaluation (follow-up time 410 ± 207 days), nail problems were more frequent (53.3%); ingrown toenail was the most common (21.6%).

CONCLUSIONS

The presence of nail alterations seems not to be caused by clubfoot pathology and could be related to unfavorable local condition in the brace.

Diagnosing nail-patella syndrome: can it be so simple?

We describe here an interesting case of a 7-day-old male infant brought with parental concerns of inability to extend both knees. Clinical evaluation revealed dysplastic fingernails, bilateral abnormal patellae, triangular lunules in conjunction with pathognomic iliac horns on pelvic radiographs suggesting the possibility of nail-patella syndrome (NPS). Other competing diagnoses with similar phenotypic features were considered and sequentially excluded. A definitive diagnosis was established by the identification of the principal mutation at the LMX1B gene locus of chromosome 9. NPS is seldom diagnosed in neonates due to the heterogeneity of clinical presentations as well as the subtlety of clinical clues in this population. NPS is a dominantly inherited disorder that is predominantly familial in origin and thus carries important implications for the prenatal diagnosis of future pregnancies as well as pre-emptive surveillance of nephropathy in the index child.

Closed-wedge Patelloplasty for the Treatment of Distal Patellofemoral Maltracking and Instability due to Severe Patellar Dysplasia: Case Report and Surgical Technique

Background

Patellofemoral maltracking is caused by different anatomical factors. Most of them are associated with a proximal maltracking, which alters the patella's engagement into the trochlear groove and predisposes the patellofemoral joint for instability. Different surgical techniques have been described to realign patellar tracking, however, most of which address proximal patellar maltracking.

Aim

The aim of this article is to demonstrate the influence of patella-related deformities on patellar tracking and to present a novel surgical technique for the treatment of distal patellar maltracking, caused by a severe patellar dyplasia.

Case Description

We report the case of a 23-year-old patient with a severe patellar dysplasia, presenting a distal patellar maltracking with recurring dislocations in deep flexion. Due to her instability, the patient was immobilised and dependent on the constant use of walking aids. Radiological images showed a concavely shaped patellar, which articulated exclusively with the lateral epicondyle and caused the patella to dislocate laterally, starting at a flexion angle of 60°. An anterior closing-wedge osteotomy was used to reshape and recenter the patella, which was complemented by a medial patellofemoral ligament reconstruction. At the 18-month follow-up, the patient presented pain free and fully remobilised, without the use of walking aids. Patellar tracking was reestablished, with a possible knee flexion until 140°. No redislocation of the patella had occurred.

Conclusion

Distal patellofemoral maltracking, caused by a severe patellar dysplasia, can successfully be treated with an anterior closed-wedge osteotomy of the patella. In combination with a medial patellofemoral ligament reconstruction, patellofemoral stability can be reestablished, to prevent further dislocations.

Clinical Significance

There are multiple factors, which may cause patellar maltracking. A thorough clinical and radiological preoperative analysis is mandatory, in order to clearly identify the underlying pathologies, as these may affect patellar tracking proximally or distally.

How to cite this article

Frings J, Freudenthaler F, Krause M, et al. Closed-wedge Patelloplasty for the Treatment of Distal Patellofemoral Maltracking and Instability due to Severe Patellar Dysplasia: Case Report and Surgical Technique. Strategies Trauma Limb Reconstr 2020;15(3):184-192.

Novel missense mutation affecting the LIM-A domain of LMX1B in a family with Nail-Patella syndrome

Nail-patella syndrome (NPS) is a rare autosomal dominant disease characterized by developmental defects of dorsal limb structures, the kidney, and the eye, that manifest as dysplastic nails, hypoplastic or absent patella, elbow dysplasia, iliac horns, glomerulopathy, and adult-onset glaucoma, respectively. This disorder is inherited in an autosomal dominant mode and is caused by heterozygous loss-of-function mutations in the LMX1B gene, which encodes the LIM homeodomain transcription factor LMX1B. In this study, we report the clinical findings of a Spanish family, from the Canary Islands, with three affected members who displayed varying phenotypes. DNA sequence analysis identified a novel heterozygous missense mutation in LMX1B, c.305A>G, p.(Y102C), that segregated with the disease. The tyrosine residue affected by the mutation is highly conserved in evolution, and is located in the LIM-A domain, next to one of the cysteine residues involved in zinc binding, suggesting that p.(Y102C) affects LMX1B function by disturbing its interactions with other proteins. Our results expand the mutation spectrum of LMX1B and provide insight into the molecular mechanisms of NPS pathology.

Nail Disorders in Children

Nail diseases in children do not account for a significant proportion of pediatric consultations, and most of the time the nails are not observed by the clinician, overlooking their importance. Specific examination of the nails is neglected, while localization to the nails could be an initial sign of a syndrome or a systemic disorder. Nail diseases in the pediatric population differ from those in adults in terms of diagnostic approach and management; some of them even are manifested mainly or exclusively in children. Pediatric patients with underlying systemic disorders are more likely to manifest acquired disorders of the nails. Although rare, nail diseases in children are a source of anxiety for the parents. Examination of the nails is an essential part of pediatric physical examination. A correct clinical history and careful examination help the clinician to distinguish the different conditions and to decide on the correct management of nail diseases in young patients. A classification of nail dystrophies according to age is somewhat arbitrary and a unique classification does not exist. Nail diseases in the pediatric population can be divided according to age groups where a predilection appears in most of the cases. Moreover, certain abnormalities may be lifelong once acquired, but their presentation may be modified by age, worsening or improving during life. This review describes many of the nail conditions that are seen in the pediatric population aging from newborn to toddler, starting with physiological aspects to better recognize the pathological conditions.