Doors Syndrome: Case Report.

DOORS syndrome is an autosomal recessive genetic neurometabolic disorder. It occurs equally in men and women. Major causes include TBC1D 24 mutations and genetic factors. Here, we discuss a 23-year-old male patient who applied to our clinic with anonychia of the toes and was diagnosed with DOORS syndrome with other accompanying clinical symptoms. Copyright:

Introduction

DOORS syndrome is a rare genetic disorder with an acronym for characteristic abnormalities associated with classical symptoms such as congenital deafness, onychodystrophy (change in nail morphology), osteodystrophy (dystrophic growth of bone) and mental retardation. Ocular and dermatoglyphic abnormalities may also be seen.[1] This syndrome, which shows autosomal recessive inheritance, is observed equally in both men and women and consanguineous marriage is the main cause. DOORS syndrome is caused by a mutation of the TBC1D24 gene.[2] Diagnosis is made by physical examination and typical characteristic features such as finger and nail abnormalities and mental retardation. Sensorineural hearing loss can be reported with audiometry/brainstem evoked response audiometry (BAER) and computerized tomography (CT) scan for demonstrating possible structural abnormalities concerning the inner ear.[123] Here, we present the case of a 23-year-old man with a late diagnosis of DOOR syndrome after admission to a dermatology clinic with anonychia.

Case Report

A 23-year-old male child of second-degree consanguineous marriage was admitted to Famagusta State Hospital Dermatology and Venerology outpatient clinic with complaints of deterioration and absence of nails in the third and fourth toes of his both feet. Dermatological examination revealed onychodystrophy white discolouration severe hypoplasia in the first and second toenails and anonychia in the fourth and fifth toes [Figure 1a and 1b]. His detailed medical history was taken from the parents the boy was born from the first pregnancy, because of spontaneous delivery at gestation week 39. Besides these signs, we realized the difficulty in pronunciation of the words, and the patient was referred to the otorhinolaryngology clinic. On ear, nose and throat (ENT) head and neck examination, asymmetric face, bilateral epicanthus, lower set ears, high arched palate and elongated uvula were observed [Figure 2a and 2b]. Developmental retardation maximally affected the motor and language milestones while cognitive and social skills were minimally delayed. Family history was unremarkable. Systemic examination including neurologic examination was normal. Ophthalmic examination was also normal. Investigations revealed mild bilateral sensorineural loss (right: 28/27 db, left 33/27 db) on an audiometric test. An intelligence test was carried out using the Wechsler Adult Intelligence Scale and an intelligence quotient (IQ) of 65 was obtained. The score was categorized as moderate mental retardation (moderate intellectual disability as per Diagnostic and Statistical Manual, fifth edition (DSM 5)). The biochemical workup was within normal limits.

Figure 1

(a and b) onychodystrophy, white discolouration, severe hypoplasia ın the first and second toenails and anonychia in the fourth and fifth toes

Figure 2

(a) Lower set ears, (b) high arched palate and elongated uvula

Interictal electroencephalogram (EEG), cerebrospinal fluid (CSF) study and magnetic resonance imaging (MRI) brain and echocardiogram all were normal. An ultrasonogram (USG) of abdomen did not show any renal abnormalities. X-ray of the foot showed on both sides with hypoplasia on the toes due to onychodystrophy. There is also adhesion in the metatarsal bones [Figure 3].

Figure 3

On both sides with hypoplasia on the toes due to onychodystrophy. There is also adhesion in the metatarsal bones

The clinical picture of the patient described above allows the diagnosis of autosomal recessive DOOR syndrome. The patient presented all of the above-mentioned main symptoms: deafness, onychodystrophy, osteodystrophy and mental retardation. Genetic testing screening could not be performed due to a lack of facilities.

Discussion

There are two types of congenital deafness associated with onychodystrophy: one dominant and the other recessive, which together have been described as a disease called DOOR syndrome. DOOR syndrome was first described in 1961 by Feinmesser and Zelig. They reported two sisters affected by consanguineous marriage.[4] Until now more than 40 cases have been reported. The genetic basis of DOOR syndrome is still controversial, but it is suspected that the disease may be caused by a mutation in a gene in an unidentified part of the mitochondrial pathway associated with oxidative phosphorylation. The disease is caused by a homozygous or compound heterozygous mutation in the gene (gene locus/MIM 613577) of family member 24 (TBC1D24) receiving TB1 on chromosome 16p13.[5]

This syndrome occurs in many variants of phenotypic appearance, in the presence of main symptoms and in laboratory investigations. A diagnosis of DOOR syndrome may be confirmed based upon a thorough clinical evaluation, detailed patient history and specialized testing, such as X-ray studies.[6] Patients with DOOR syndrome also typically have characteristic abnormalities in the structure, texture and colour of fingernails and toenails. Such abnormalities include misshapen, discoloured, underdeveloped (hypoplastic) and/or rudimentary nails or even absence of nails. They may also have varying degrees of intellectual disability from mild to severe and, in some cases, variable delays in reaching speech.[5] During the first year of life, some affected infants may begin to experience sudden episodes of uncontrolled electrical activity in the brain, particularly grand mal seizures.

Among the differential diagnoses, Coffin–Siris syndrome (no deafness), Zimmerman Laband syndrome (hepatosplenomegaly is present but mental retardation and deafness are not evident), fetal hydantoin syndrome and fetal alcohol syndrome should be considered.[78] Associated symptoms or diseases in this syndrome must be treated.

Our case report was a male child of consanguineous marriage. General examination revealed dysmorphic features like anonychia (absence of nail), low set ears and osteodystrophy.

In conclusion, DOOR syndrome is a genetic disorder with recognizable facial features and a progressive natural history. In this presented case, the presence of deafness, abnormal nail structure in the hands and feet, accompanying osteodystrophy and mental retardation should be considered clinically as a possible diagnosis of DOOR syndrome. Congenital abnormal nails or phalanges based on the embryological process highlight the importance of detailed hearing screening.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.