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.

Schinzel-Giedion syndrome (SGS) is a severe multisystem disorder characterized by distinctive facial features, profound intellectual disability, refractory epilepsy, cortical visual impairment, hearing loss, and various congenital anomalies. SGS is attributed to gain-of-function (GoF) variants in the SETBP1 gene, with reported variants causing canonical SGS located within a 12 bp hotspot region encoding SETBP1 residues aa868-871 (degron). Here, we describe a case of typical SGS caused by a novel heterozygous missense variant, D874V, adjacent to the degron. The female patient was diagnosed in the neonatal period and presented with characteristic facial phenotype (midface retraction, prominent forehead, and low-set ears), bilateral symmetrical talipes equinovarus, overlapping toes, and severe bilateral hydronephrosis accompanied by congenital heart disease, consistent with canonical SGS. This is the first report of a typical SGS caused by a, SETBP1 non-degron missense variant. This case expands the genetic spectrum of SGS and provides new insights into genotype-phenotype correlations.

本文报道了1例Heimler综合征患儿，并确定了该家系的分子遗传基础，先证者携带NM_000466.3（PEX1）：c.2966T>C（p.Ile989Thr）和c.2783+2T>C两个变异位点。经Sanger测序验证c.2966T>C位点变异遗传自其母亲，c.2783+2T>C变异位点遗传自其父亲，并结合RNA测序进行变异功能验证，两个变异评级为致病。.

UNASSIGNED: Onychocytic matricoma (OCM) is a benign neoplasm of the nail matrix. Only 18 cases of this tumor have been reported in the literature to date. We retrospectively analyzed the clinical features of 14 patients with OCM. The most common clinical feature was longitudinal xanthopachyonychia (n = 9), followed by longitudinal leukopachyonychia (=3) and longitudinal pachymelanonychia (n = 2). The most common clinical findings identified following dermoscopy and analysis at high magnification of classical photographs were free-edge thickening of the nail plate without pitting (n = 14), longitudinal ridging (n = 7), round white clods (n = 7), white dots (n = 7), and filiform hemorrhages (n = 7), followed by oval and linear white clods (n = 5), fuzzy lateral border (n = 5), and red-purple blood clods (n = 3). Nail clipping histopathology showed a thickened nail plate with multiple, small, round-to-oval spaces. The tumor expressed immunopositivity for LEF-1. Dermoscopy of the nail plate and nail clipping histology provides useful information with regards to the differential diagnosis with subungual squamous cell carcinoma and nail melanoma. Ex vivo-in vivo correlation facilitates a better dermoscopic assessment of this unique underrecognized disease. However, the differential diagnosis between OCM and onychocytic carcinoma requires biopsy of the tumor. LEF-1 as an onychogenic marker can be used to resolve the differential diagnosis between OCM and subungual longitudinal acanthoma/seborrheic keratosis.

Dermatologic literature describes nail abnormalities involving nail bed as linear erythronychia or onychomatricoma. The abnormality reflects cognitive content of the nail bed. A resourceful epidermis capable of manifesting in a variety of clinical appearances depends on initiating stimulus affecting remarkably its nail bed matrix cells. These cells are stem cells (NBMSC) migrating distally to cover remarkably the underlying nail bed dermal ridges that are homologous to finger print dermal ridges. Normally, adult nail bed epidermal cells are uniform and keratinize with the stratum corneum without a granular layer.

Individuals with psoriatic nails often have a lower quality of life relative to their counterparts with healthy nails. Methotrexate (MTX), an anti-neoplastic agent, is a longstanding treatment option for nail psoriasis. In the current study, we compared the effects of MTX to that of a corticosteroid, namely, methylprednisolone acetate (i.e., Depo-Medrol®) across individuals with nail psoriasis. We used a cohort study design, and both agents were administered intralesionally. Outcome variables were based on the Nail Psoriasis Severity Index (NAPSI). We quantified the effect in terms of change in NAPSI, complete cure at week 16, and cure between 32 and 36 weeks. Our regressions demonstrated that reduced NAPSI scores with Depo-Medrol were, on average, greater than that with MTX by 2.27 (n = 48, P = 0.000255) at week 16. Similarly, the odds of complete cure at week 16 was greater with Depo-Medrol® than with MTX (odds ratio = 18.6, P < 0.0001). In terms of both complete cure and change in NAPSI, Depo-Medrol® was significantly more effective than MTX at a follow-up period of 32-36 weeks. Our study established that intralesional Depo-Medrol® is more effective than intralesional methotrexate for treating nail psoriasis.

Pathogenic variants of the KCNH1 gene can cause dominant-inherited Temple-Baraitser/Zimmermann-Laband syndrome with severe mental retardation, seizure, gingival hyperplasia and nail hypoplasia. This study established an induced pluripotent stem cell (iPSC) line using urinary cells from a girl with KCNH1 recurrent/hotspot pathogenic variant c.1070G > A (p.R357Q). The cell identity, pluripotency, karyotypic integrity, absence of reprogramming virus and mycoplasma contamination, and differential potential to three germ layers of the iPSC line, named as ZJUCHi003, were characterized and confirmed. Furthermore, ZJUCHi003-derived neurons manifested slower action potential repolarization process and wider action potential half-width than the normal neurons. This cell line will be useful for investigating the pathogenic mechanisms of KCNH1 variants-associated symptoms, as well as for evaluating novel therapeutic approaches.

BACKGROUND: Coffin-Siris Syndrome (CSS) is a rare genetic disorder of unknown etiology. It combines digital-ungual abnormalities, facial dysmorphism, developmental and intellectual delay, and other organ-system abnormalities. Oral and dental anomalies are rarer.
METHODS: 8-year-old boy with clinical diagnosis of CSS presented facial dysmorphism, sparse hair, a flat and wide nose, absence of nails on 3rd and 5th fingers of the right hand and 3rd and 4th fingers of the left hand, malformation of the feet, toes with nail hypoplasia. Oral and dental anomalies included : bilateral complete cleft lip and palate, delayed eruption of permanent teeth, presence of supernumerary tooth and taurodontism in the first permanent molars.
CONCLUSIONS: Early diagnosis of oral problems and regular follow-up in dentist are necessary to promote good oral health and improve the patient\'s quality of life.

Injuries to the fingertips are the most frequently occurring damage to the hand. The nail is an exceptional structure within the human body that offers both stability and protection, as well as the ability to perform fine and precise movements. Nail dystrophies are numerous, post-traumatic, post-infection or even degenerative. They raise many difficulties for the treating hand surgeon. Which anatomical structure is dystrophic? Is there any secondary fungal superinfection to be treated before surgery? Among the various techniques proposed, which one will help to improve my patient as a complete cure is rarer than partial failures. In this chapter we have chosen to describe the surgical techniques, their difficulties and drawbacks, that are available for the most frequent dystrophies that the hand surgeons may treat.

Hook-nail deformity is frequently seen after a fingertip amputation, whether or not flap reconstruction has been done. It is more frequent if the bony support is missing. The deformity results in esthetic and functional impairment which can lead to complete finger amputation. Correction is surgical, but is difficult and surgical series are small. Soft-tissue flap augmentation is simple, but does not add a bony support. Bone augmentation using local flaps is limited by the small size of the distal phalanx remnant. Toe transfer is more logical but, as it is a highly demanding technique, only a few cases have been published. The present study sought to review all the published techniques and their results, to help the reader choose the one best suited to their patient.