18q Deletion Syndrome Presenting with Late-Onset Combined Immunodeficiency.

Patients with chromosome 18q deletion syndrome generally experience hypogammaglobulinemia. Herein, we describe two patients with chromosome 18q deletion syndrome who presented with late-onset combined immune deficiency (LOCID), which has not been previously reported. Patient 1 was a 29-year-old male with 18q deletion syndrome, who was being managed for severe motor and intellectual disabilities at the Yamabiko Medical Welfare Center for 26 years. Although the patient had few infections, he developed Pneumocystis pneumonia at the age of 28. Patient 2, a 48-year-old female with intellectual disability and congenital malformations, was referred to Tokyo Medical and Dental University Hospital with abnormal bilateral lung shadows detected on her chest radiography. Computed tomography showed multiple lymphadenopathies and pneumonia. A lymph node biopsy of the inguinal region revealed granulomatous lymphadenitis, and a chromosomal examination revealed 18q deletion. Array-based genomic hybridization analysis revealed deletion at 18q21.32-q22.3 for patient 1 and at 18q21.33-qter for patient 2. Immune status work-up of the two patients revealed panhypogammaglobulinemia, decreased number of memory B cells and naïve CD4+ and/or CD8+ cells, reduced response on the carboxyfluorescein diacetate succinimidyl ester T-cell division test, and low levels of T-cell receptor recombination excision circles and Ig κ-deleting recombination excision circles. Consequently, both patients were diagnosed with LOCID. Although patients with 18q deletion syndrome generally experience humoral immunodeficiency, the disease can be further complicated by cell-mediated immunodeficiency, causing combined immunodeficiency. Therefore, patients with 18q deletion syndrome should be regularly tested for cellular/humoral immunocompetence.

New osseous soft markers for trisomy 13, 18 and 21.

INTRODUCTION: For ultrasonographic diagnosis of a fetal trisomy so-called "soft markers" (=ultrasonographically detectable morphological variants) are used. Detection of a certain number of them increases the diagnostic certainty of a fetal trisomy. Up to now there are very few diagnostically accepted osseous soft markers for trisomy. Hence potential osseous soft markers applicable for first and second trimester ultrasound screening for trisomy 21, 18 or 13 were studied. METHODS: Postmortal fetal X-rays (ap, lateral) of 358 fetuses (trisomy 21: n = 109, trisomy 18: n = 46; trisomy 13: n = 38, control group: n = 165). RESULTS: Not yet described but with trisomy 21 statistically associated soft markers were un-timely os sternale ossification, delayed os sacrum ossification, shortened os maxillare, reduced os maxillare-jaw-corner distance, augmented orbita height, premature os calcaneus ossification, bell-shaped thorax, coronal clefts, trend to wider binocular as well as wider intraocular distances; for trisomy 18: elevated clavicula slope, reduced number of ribs, bell-shaped thorax, coronal clefts, reduced os maxillare-jaw-corner distance, shortened ramus mandibulare, shortened os metacarpale IV and V, augmented ratio between biparietal diameter and (osseus and soft-tissue) shoulder width; for trisomy 13: longer os nasale, elevated clavicula slope, premature sternum, delayed os sacrum ossification, delayed/premature cranium ossification, reduced number of ribs, coronal clefts, reduced os maxillare-jaw-corner distance, shortened ramus mandibulare, augmented orbita height, shortened os metacarpale V and a tendency for a shortened os metacarpale IV. CONCLUSION: We found several not yet published osseous soft markers statistically associated with trisomy 21, 18 and 13, which can help to ensure sonographically these aneuploidy diagnoses.

Central nervous system abnormalities and psychomotor retardation in a girl with a 15.4-MB deletion of 14q12→q21.2 and a 550-KB deletion of 18p11.23: microarray delineation of an unbalanced chromosome rearrangement and a literature review.

This paper describes the presence of a 15.4 Mb deletion of 14q12→q21.2 and a 550-KB deletion of 18p11.23 in a patient with an apparently balanced translocation between chromosomes 14 and 18 [t( 14; 18) (ql2; pi 11)]. The patient had developmental delay, truncal hypotonia, hyperreflexia and spasticity of the lower extremities, prominent forehead, fullness of the periorbital region, hypertelorism, upslanted palpebral fissures, systagmus, a depressed nasal bridge, down-turned conrners of the mouth, a prominent philtrum, thin upper lip, pointed chin, and deep palmar creases. Cranial MRI revealed agenesis of the corpus callosum, diffuse cerebral atrophy, and enlargement of the third and lateral ventricles. Here, we review and compare published cases with proximal 14q deletions to establish a genotype-phenotype correlation according to the deleted regions involving the 14q12, 14q13, 14q21, and 14q22q23. We also examined the literature to find cases with deleted regions overlapping the deletion in our patient to establish a clinical spectrum in proximal 14q deletions.

[Trisomy 18 syndrome: A case report]. / Síndrome de trisomía 18. Reporte de un caso clínico.

INTRODUCTION: The trisomy 18 syndrome occurs due to the presence of an extra chromosome 18 in most cases. The prevalence in infants is estimated at 1:6000 to 1:8000. Those affected have a high mortality rate, only 4% may survive their first year of life. There are few reported cases exceeding five years of age. OBJECTIVE: The aim of this paper is to report a case of trisomy 18 of long survival with oral cavity features not described in the literature, and to provide information to physicians and paediatricians about aetiology, phenotype, survival and genetic counselling. CASE REPORT: A 7 year-old female patient with 2 karyotypes performed by lymphocyte culture showing 47XX+18 in all metaphases. She presented with growth deficiency, dysmorphic facies, severe psychomotor retardation and cognitive disability, inability to feed, lack of verbal language, sensorineural hearing loss, ataxia, cerebellar hypoplasia, and genitals with hypoplastic labia majora and minora. In the oral cavity: dome shaped palate, macroglossia, absence of upper central incisors and first upper and lower molars in mouth. X-ray findings showed formation of missing teeth, with late eruption being concluded. CONCLUSIONS: In cases of trisomy 18 syndrome there is an increased risk of neonatal and infant mortality. The clinical characteristics in utero and in neonates have been well described. Since few cases exceeding five years of age have been reported, the phenotype is yet to be established. In the case being reported we describe oral cavity findings not documented in the literature.

Genotypic and phenotypic variation in six patients with solitary median maxillary central incisor syndrome.

Solitary Median Maxillary Central Incisor occurs in 1 of 50,000 live births. It is the mildest manifestation of the holoprosencephaly spectrum and is genetically heterogeneous. Here we report six patients with solitary median maxillary central incisor, and a range of other phenotypic anomalies with different degrees of severity, varying from mild signs of holoprosencephaly to associated intellectual disability, and with different genetic background. Using array comparative genomic hybridization, pathogenic copy number variants were found in three of the six patients. Two patients had a deletion at the 18p11 chromosomal region that includes TGIF1 while the other patient had a deletion at 7q36, including the SHH gene. In one patient, a mutation in SIX3 was detected with exome sequencing, while in the two remaining patients all known holoprosencephaly genes were excluded using multiplex ligation-dependent probe amplification and sequencing, and remain unsolved. One of the two latter patients had isolated solitary median maxillary central incisor without other visible dentofacial anomalies, while the other had clinical features not part of the known holoprosencephaly spectrum.

Facial profile markers in second- and third-trimester fetuses with trisomy 18.

OBJECTIVES: To evaluate nasal bone length (NBL), maxilla-nasion-mandible (MNM) angle, fetal profile (FP) line, prenasal thickness (PT), prenasal thickness to nasal bone length (PT:NBL) ratio and prefrontal space ratio (PFSR) as markers of trisomy 18 in the second and third trimesters of pregnancy. METHODS: The NBL, MNM angle, FP line, PT, PT:NBL ratio and PFSR were measured retrospectively from stored two-dimensional images or three-dimensional volumes of trisomy-18 fetuses, and were compared with our previously reported normal ranges for euploid fetuses. Additional ultrasound findings were noted at initial routine second-trimester scan and at subsequent advanced ultrasound examination performed after referral for karyotyping. RESULTS: A total of 43 trisomy-18 fetuses were included in the analysis. At initial examination, median gestational age was 21 + 2 weeks. NBL and PT were correlated with gestational age (P < 0.001), but the other markers were not. Mean NBL, MNM angle, PT, PT:NBL ratio and PFSR were 3.76 mm, 16.67°, 4.25 mm, 1.39 and 0.87, respectively. The FP line was zero (normal) in 53.7% of cases and negative (abnormal) in 46.3%. All markers were significantly associated with trisomy 18, with the PT:NBL ratio yielding the highest detection rate (88.4%) followed by NBL (83.7%), MNM angle (56.4%), FP line (46.3%), PT (27.9%) and the PFSR (20.5%) (for a 5% false-positive rate for the continuous variables). Various combinations of the four best markers (NBL, FP line, MNM angle and PT:NBL ratio) yielded detection rates of between 72% and 95%. Structural anomalies were not detected in 22% of fetuses at the initial scan and in 2% at the advanced scan. CONCLUSIONS: The PT:NBL ratio and NBL are robust second- and third-trimester markers for trisomy 18. A negative FP line has a 0% false-positive rate and the potential to differentiate between trisomy 18 and Down syndrome, as in the latter the FP line is often positive. No major anomaly was observed at the initial scan in about a quarter of trisomy-18 fetuses, underlining the role of second-trimester facial marker evaluation.

Genome-wide association study of primary dentition pit-and-fissure and smooth surface caries.

Dental caries continues to be the most common chronic disease in children today. Despite the substantial involvement of genetics in the process of caries development, the specific genes contributing to dental caries remain largely unknown. We performed separate genome-wide association studies of smooth and pit-and-fissure tooth surface caries experience in the primary dentitions of self-reported white children in two samples from Iowa and rural Appalachia. In total, 1,006 children (ages 3-12 years) were included for smooth surface analysis, and 979 children (ages 4-14 years) for pit-and-fissure surface analysis. Associations were tested for more than 1.2 million single nucleotide polymorphisms, either genotyped or imputed. We detected genome-wide significant signals in KPNA4 (p value = 2.0E-9), and suggestive signals in ITGAL (p value = 2.1E-7) and PLUNC family genes (p value = 2.0E-6), thus nominating these novel loci as putative caries susceptibility genes. We also replicated associations observed in previous studies for MPPED2 (p value = 6.9E-6), AJAP1 (p value = 1.6E-6) and RPS6KA2 (p value = 7.3E-6). Replication of these associations in additional samples, as well as experimental studies to determine the biological functions of associated genetic variants, are warranted. Ultimately, efforts such as this may lead to a better understanding of caries etiology, and could eventually facilitate the development of new interventions and preventive measures.

The frontal space measurement in euploid and aneuploid pregnancies at 11-13 weeks' gestation.

OBJECTIVE: The aim of this study is to evaluate whether the measurement of the frontal space (FS) improves first trimester combined aneuploidy screening. METHODS: We have presented a retrospective study including 2D images of the nuchal translucency measurement of 300 euploid and 133 trisomic fetuses that were seen at the prenatal department at the University of Tuebingen, Germany. For the FS measurement, a mandibulo-maxillary line (MML) was created by connecting the anterior edge of the mental protuberance and anterior edge of the maxilla. The MML was then extended upwards. A measurement was taken perpendicular from the MML to the skin line over the point of largest excursion of the fetal forehead. After transformation into z-scores based on the crown rump length, the FS distribution in fetuses with trisomy 21, 18, and 13 was compared with the euploid group by using a student's t-test. RESULTS: The mean FS in euploid fetuses was 1.25 mm. In fetuses with trisomy 21, 18, and 13, the mean FS measurements were 2.96, 3.22, and 2.03 mm. In euploid and trisomy 21, 18, and 13 pregnancies, FS measurements were above the 95th centile in 5.3%, 41.1%, 34.3%, and 12.5% of the cases. The mean z-scores were significantly higher in trisomy 21 and 18. CONCLUSION: First trimester FS measurement may improve first trimester combined screening.

Cytogenetics of central giant cell granuloma of the mandible.

PURPOSE: Central giant cell granuloma is a benign entity that commonly occurs in the mandible and maxilla. It is usually treated by surgical excision, varying from curettage to en bloc resection. Because the entity is more common in diseases such as neurofibromatosis, a genetic element may be involved in its pathogenesis. Cytogenetic studies of central giant cell granuloma affecting bone are rare, and to the authors' knowledge, there are none reported in the literature for central giant cell granuloma of the mandible. MATERIALS AND METHODS: The authors investigated the cytogenetic profile of a case occurring in the mandible. Fresh biopsy tissue was minced and cultured in RPMI-1640 medium. Cells were fixed and stained, and cytogenetic analysis was performed according to standard procedures. RESULTS: A clone with t(1;17;18) and other random numerical chromosomal changes was found. CONCLUSIONS: The significance of these findings in diagnosis and prognosis is currently unclear and further karyotyping studies are needed to more fully understand this tumor.

Oral Care in a Patient with Long Arm Deletion Syndrome of Chromosome 18: A Narrative Review and Case Presentation.

BACKGROUND Long arm (q) deletion syndrome of chromosome 18 is a congenital chromosomal disorder. The specialist dental management of patients with 18q deletion is a challenge, as these individuals fall into the category of patients with special needs. The aim of this work was to describe the surgical and dental management in hospital of a patient with long arm deletion syndrome of chromosome 18 (18q). CASE REPORT An 8-year-old patient with deletion syndrome of chromosome 18 (18q) was referred to the Department of Dentistry and Oral Surgery. The patient presented dental pain and difficult feeding. The examination of the oral cavity revealed a destructive carious lesion of the lower right second deciduous molar and the need to perform a frenectomy due to the short lingual frenulum, which limited the movements of the tongue. Given the complex management of the patient, it was necessary to carry out surgical procedures in the operating room. Frenectomies of the lower labial and lingual frenulum were carried out with the aid of an electric scalpel with an ultra-sharp microdissection needle. At 2-month follow-up, the patient presented with good extraction site healing and satisfactory lingual mobility, along with improvements of speech and feeding. CONCLUSIONS Dental involvement in patients with deletion syndrome of the long arm of chromosome 18 is poorly documented in the literature. The hospital regimen appears to be the criterion standard for the management of the patient with long arm deletion syndrome of chromosome 18.

Clinical Characteristics and Long-Term Recombinant Human Growth Hormone Treatment of 18q- Syndrome: A Case Report and Literature Review.

Background: 18q- syndrome is a rare chromosomal disease caused by the deletion of the long arm of chromosome 18. Some cases with 18q- syndrome can be combined with growth hormone deficiency (GHD), but data on the efficacy of recombinant human growth hormone (rhGH) treatment in 18q- syndrome are limited. Methods: Here, we report one case of 18q- syndrome successfully treated with long-term rhGH supplement. Previously reported cases in the literature are also reviewed to investigate the karyotype-phenotype relationship and their therapeutic response to rhGH. Results: A 7.9-year-old girl was referred for evaluation for short stature. Physical exam revealed proportionally short stature with a height of 111.10 cm (-3.02 SD score (SDS)), low-set ears, a high-arched palate, a small jaw, webbed neck, widely spaced nipples, long and tapering fingers, and cubitus valgus. Thyroid function test indicated subclinical hypothyroidism. The peak value of growth hormone was 10.26 ng/ml in the levodopa provocation test. Insulin-like growth factor 1 (IGF-1) was 126 ng/ml (57-316 ng/ml). Other laboratory investigations, including complete blood cell count, liver and kidney function, gonadal function, serum adrenocorticotropin levels, and serum cortisol levels, were all within normal ranges. Karyotype analysis showed 46, XX, del (18) (q21). L-Thyroxine replacement and rhGH treatment were initiated and maintained in the following 7 years. At the age of 14.8, her height has reached 159.5 cm with a height SDS increase of 2.82 SDS (from -3.02 SDS to -0.20 SDS). No significant side effects were found during the treatment. The literature review indicated the average rhGH treatment duration of 16 patients was 5.9 ± 3.3 years, and the average height SDS significantly increased from -3.12 ± 0.94 SDS to -1.38 ± 1.29 SDS after the rhGH treatment (p < 0.0001). Conclusion: The main clinical manifestations of 18q- syndrome include characteristic appearance, intellectual disability, and abnormal genital development. The literature review suggested a significant height benefit for short stature with 18q- syndrome from long-term rhGH treatment.

Interstitial deletion of 18q: comparative genomic hybridization array analysis of 46, XX,del(18)(q21.2.q21.33).

BACKGROUND: Interstitial deletion of chromosome 18q is rare, making it difficult to assign phenotypes to particular cytogenetic deletions. CASE: We present an 18-year-old female with an interstitial deletion of chromosome 18q21.2-q21.33. The clinical features included severe psychomotor retardation with mild growth retardation, hypotonia, midfacial hypoplasia, carp-shaped mouth, hypertelorism, strabismus, narrow upward slant palpebral fissures, short philtrum, everted lower lip, malformed ears, flat nasal bridge, and epicanthic folds. Brain abnormalities, such as agenesis of the corpus callosum, and abnormalities of the hands and feet were absent. Initially, the deletion was recognized as 18q21.1-q21.31 by conventional chromosomal analysis, and microarray-based comparative genomic hybridization revealed a 9.6-Mb deletion at 18q21.2-q21.33. The deletion included the transcription factor 4 gene and the methyl-CpG binding domain protein 2 (MBD2) gene, but not the MBD1 gene. CONCLUSIONS: The deletion of the transcription factor 4 gene suggested a possible contribution of the deletion to the patient's facial abnormalities, as observed in Pitt-Hopkins syndrome. Together with other reported cases with interstitial deletion of 18q, a possible contribution of haploinsufficiency in both MBD1 and MBD2 genes to a Rett syndrome-like phenotype was suggested, but further genetic studies on other cases are necessary to clarify the genotype-phenotype correlation.

Neonatal experiences of newborns with full trisomy 18.

PURPOSE: To provide information about neonatal experiences for newborns with full trisomy 18 (t18). SUBJECTS: Mothers of 21 newborns with full t18 (13 survivors; 8 who died prior to mothers' participation in the study). DESIGN: Mixed method, descriptive, online survey. METHODS: Subjects completed an online survey. Data were downloaded into an SPSS database. Descriptive statistics were used to analyze resulting data. MAIN OUTCOME MEASURES: Subjects' responses on Tracking Rare Incidence Syndromes survey. PRINCIPAL RESULTS: Newborns presented with syndrome-related physical characteristics (eg, low-set ears, small jaw) and medical conditions (eg, heart defects). Gestational age was generally older than what is described in the existent literature. In the NICU, newborns were provided with a variety of equipments (eg, nasal cannula, pulse oximeter) and received treatments including blood transfusions and echocardiograms. Data also indicate longer survival rates (103.3 months for survivors, 37.5 months for nonsurvivors) than that described in the literature. CONCLUSIONS: Data indicate presence of common presenting physical and medical characteristics and varied medical assistance to newborns with full t18.

A case with a rare chromosomal abnormality: isochromosome 18p.

Isochromosome 18p (i(18p)), is a rare chromosomal disorder that occurs once in about every 140,000 live births and affects males and females equally. Most of the cases are due to a de novo formation but in the literature familial cases were reported. Here, we report a young female with dysmorphic features as microcephaly, frontal bossing, strabismus, low-set ears, small pinched up nose, small mouth, high palate and long philtrum, presenting a small metacentric chromosome. Besides the dysmorphic features she also has gastroesophageal reflux, spasticity, strabismus and specific brain MRI findings as dilatation of the right lateral ventricle trigonum occipital horn (colpocephaly), thinning of the corpus callosum especially of the posterior part and abnormality of the white matter myelinisation at the frontal and occipital region. Particularly the MR findings are rarely reported in the literature.

The variable phenotype in tetrasomy 18p syndrome. A propos of a subtle dysmorphic case.

The variable phenotype in tetrasomy 18p syndrome. Apropos of a subtle dysmorphic case: Tetrasomy 18 is a rare chromosomal syndrome. Its frequency is 1/40,000 newborns and more than 40 cases have been reported. In this paper we report a 25-month-old female patient referred for chromosome examination essentially because of delayed psychomotor development. The physical examination showed: microcephaly, mild generalized spasticity, arched eyebrows, horizontal palpebral fissures with unilateral convergent strabismus, bilateral epicanthic folds, small nose, well placed ears, oral cavity with high arched palate and upper vestibular frenula, tented mouth with slightly everted upper lip, hands with normal palmar creases and long fingers. All the blood tests were normal, while the magnetic resonance imaging reported mild demyelination and polymicrogyria. The karyotype was 47,XX,+i(18)(p10).ish i(18)(plO)(D18Z1+) de novo.

A case of ring chromosome 18 syndrome treated with a combined orthodontic-prosthodontic approach.

OBJECTIVE: The aim of this study was to report the case of a Japanese subject with ring chromosome 18 syndrome. A cephalometric analysis was performed, and the treatment procedure is described. DESIGN: Lateral and posteroanterior cephalograms were compared with Japanese norms. Dental anomalies were evaluated by a model analysis. The outcome of orthodontic-prosthodontic treatment was evaluated by comparing cephalograms during the course of treatment. RESULTS: The cephalometric analysis showed a reduction in the cranial base length and cranial width, midfacial depth, and height and width. Comparison of lateral cephalograms at age 16 years 6 months and 22 years 4 months showed late growth of the mandible. The model analysis showed that all of the teeth, except for the mandibular canine, were small. CONCLUSIONS: Characteristic craniofacial and dental anomalies were clarified. Successful oral rehabilitation was achieved by combined orthodontic-prosthodontic treatment.

Chromosomal Repositioning and Gene Regulation of Cells on a Micropillar Array.

While various cell responses on material surfaces have been examined, relatively few reports are focused on significant self-deformation of cell nuclei and corresponding chromosomal repositioning. Herein, we prepared a micropillar array of poly(lactide-co-glycolide) (PLGA) and observed significant nuclear deformation of HeLa cells on the polymeric micropillars. In particular, we detected the territory positioning of chromosomes 18 and 19 and gene expression profiles of HeLa cells on the micropillar array using fluorescence in situ hybridization and a DNA microarray. Chromosome 18 was found to be translocated closer to the nuclear periphery than chromosome 19 on the micropillar array. With the repositioning of chromosomal territories, HeLa cells changed their gene expressions on the micropillar array with 180 genes upregulated and 255 genes downregulated for all of the 23 pairs of chromosomes under the experimental conditions and the employed Bioinformatics criteria. Hence, this work deepens the understanding on cell-material interactions by revealing that material surface topography can probably influence chromosomal repositioning in the nuclei and gene expressions of cells.

TCF4 deletions in Pitt-Hopkins Syndrome.

Pitt-Hopkins syndrome (PHS) is a probably underdiagnosed, syndromic mental retardation disorder, marked by hyperventilation episodes and characteristic dysmorphism (large beaked nose, wide mouth, fleshy lips, and clubbed fingertips). PHS was shown to be caused by de novo heterozygous mutations of the TCF4 gene, located in 18q21. We selected for this study 30 unrelated patients whose phenotype overlapped PHS but which had been initially addressed for Angelman, Mowat-Wilson, or Rett syndromes. In 10 patients we identified nine novel mutations (four large cryptic deletions, including one in mosaic, and five small deletions), and a recurrent one. So far, a total of 20 different TCF4 gene mutations have been reported, most of which either consist in deletion of significant portions of the TCF4 coding sequence, or generate premature stop codons. No obvious departure was observed between the patients harboring point mutations and large deletions at the 18q21 locus, further supporting TCF4 haploinsufficiency as the molecular mechanism underling PHS. In this report, we also further specify the phenotypic spectrum of PHS, enlarged to behavior, with aim to increase the rate and specificity of PHS diagnosis.

Disruption of the TCF4 gene in a girl with mental retardation but without the classical Pitt-Hopkins syndrome.

We have characterized a de novo balanced translocation t(18;20)(q21.1;q11.2) in a female patient with mild to moderate mental retardation (MR) and minor facial anomalies. Breakpoint-mapping by fluorescence in situ hybridization indicated that on chromosome 18, the basic helix-loop-helix transcription factor TCF4 gene is disrupted by the breakpoint. TCF4 plays a role in cell fate determination and differentiation. Only recently, mutations in this gene have been shown to result in Pitt-Hopkins syndrome (PHS), defined by severe MR, epilepsy, mild growth retardation, microcephaly, daily bouts of hyperventilation starting in infancy, and distinctive facial features with deep-set eyes, broad nasal bridge, and wide mouth with widely spaced teeth. Breakpoint mapping on the derivative chromosome 20 indicated that here the rearrangement disrupted the chromodomain helicase DNA binding protein 6 (CHD6) gene. To date, there is no indication that CHD6 is involved in disease. Our study indicates that TCF4 gene mutations are not always associated with classical PHS but can give rise to a much milder clinical phenotype. Thus, the possibility exists that more patients with a less severe encephalopathy carry a mutation in this gene.

A child with 18p- syndrome: a case report.

18p- syndrome is caused by the deletion of all or a portion of genetic material on the short (p) arm of chromosome 18. It was first described in 1963 and since then there have been a variety of clinical characteristics associated with this syndrome. The patient described presented with learning difficulties, epilepsy, a characteristic round face and anti-mongoloid slant to the eyes. Orally he had a single maxillary central incisor and a high caries rate which necessitated comprehensive dental treatment under general anesthesia.