A case report of seckel syndrome

INTRODUCTION

Seckel syndrome, first defined by Seckel in 1960,¹ is a rare condition with a reported incidence of 1:10,000 live births.² The skeleton of the affected person whom Seckel studied is now in the Hunterian Museum of the Royal college of Surgeons, London. It is the most common of the microcephalic osteodysplastic dwarfisms.³ Rudolf Virchow introduced the term “bird‑headed dwarf ” in the context of proportionate dwarfism with low birth weight, mental retardation, a pointed nose, and micrognathia.⁴ In 1967 McKusick and colleaguesdocumented this condition in three out of eleven siblings and suggested that inheritance was autosomal recessive.⁵ This syndrome is considered to be a variant of Harper’s syndrome.

Case Report

Two male siblings 15 years (case 1) and 9 years (Case 2) reported to the Department of Pedodontics and Preventive Dentistry with a chief complaint of over retained teeth. History revealed that the patients were born due to consanguineous marriage and presented with delayed developmental milestones and severe growth retardation but normal mental growth. They had an older sibling of normal physical appearance and normal mental growth. Based on the history, delayed developmental status and clinical findings, a diagnosis of Seckel syndrome was made.

Case 1

On general examination, patient had short stature with weight being 15 kgs, and height being 113 cms, birth weight being 1.5 kgs, On physical examination, patient presented with receding forehead, prominent eyes, pointed nose, and micrognathia, the characteristic features of “bird‑headed dwarf ”. On extraoral examination, there was lip incompetency. On intraoral hard tissue examination, patient presented V shaped arch, mixed dentition with 27 teeth, and Ellis and Davey’s class II fracture with 11 and 21. Overretained tooth with 74. Class 1 dentoskeletal pattern with increased overjet was observed. Dental treatment including oral prophylaxis, extraction of 74 and composite restoration with 11 and 12 was done.

Case 2

On general examination, patient had short stature with weight being 11 kgs and height being 98 cms, birth weight being 1.4 kgs. On physical examination, patient presented with receding forehead, prominent eyes, pointed nose, and micrognathia, the characteristic features of “bird‑headed dwarf ”. On extraoral examination, there was lip incompetency.

On intraoral hard tissue examination, the patient presented mixed dentition with microdontia in all 25 teeth. Dental caries was evident with 54,55,64,65,74,75,85. Grossly decayed 84, 61. Over-retained 71 and 81, Class 1 dentoskeletal pattern with increased woverjet was observed. Treatment including oral prophylaxis, extraction with 61,71,81,84. Glass ionomer cement restorations with 54,55,64,65,74,75,85 was done.

DISCUSSION

Seckel syndrome is a rare constellation of malformations, presumably inherited as an autosomalrecessive inherited trait. The male to female sex ratio is 9:11. This syndrome is a heterogeneous form of primordial dwarfism.⁵ The synonyms of this syndrome include Seckel dwarfism, bird‑headed dwarfism, nanocephalic dwarfism, and microcephalic primordial dwarfism.³

Seckel syndrome encompasses a number of facial and brain abnormalities possibly associated with prenatal and postnatal growth restriction.6 The syndrome is characterized by intrauterine growth retardation (average birth weight 1540 g) and severe proportionately short stature with severe microcephaly.³ They also present with mental retardation and are easily distracted.

In the present case, developmental history revealed delayed developmental milestones and severe growth retardation with normal mental growth. Parents were unaffected and the children were born from a consangunious marriage.

The etiopathogenesis of this syndrome remains unclear.5 The mode of inheritance in Seckel syndrome is thought to be autosomal recessive.

Advances in molecular genetics have shown some aberration in a few chromosomes also it can be due to increased chromosomal instability or chromosomal breakage.¹ Chromosomal aberrations causing Seckel syndrome have been reported in earlier studies in genes 2q33.3‑34,⁷ 18p11.31‑q11.2,8 and 3q22.1‑q24.⁹

Clinical facial features of this syndrome include “bird‑headed profile” with receding forehead, large eyes, beak-like protrusion of the nose, narrow face, receding lower jaw, and micrognathia.⁹ In the present case, the patient presented with characteristic features of a “bird‑headed profile”. Other occasional features include high-arched palate, cleft palate, malocclusion, enamel hypoplasia, premature closure of cranial sutures secondary to diminished brain growth, antimongoloid slant of palpebral fissures, dysplastic ears, clinodactyly of the fifth fingers, cryptorchidism, clitoridomegaly, hirsutism, agenesis of corpus callosum, pachygyria, retarded bone age, frequent hip dysplasia, low-set ears, and 11 pairs of ribs.¹ In addition, abnormalities have been found in cardiovascular, hematopoietic, and endocrine, as well as nervous system.¹

The primary diagnostic features are severe intrauterine growth retardation, microcephaly, characteristic “bird‑headed profile”, and mental retardation.⁵ In most cases, diagnosis depends upon recognition of clinical findings.³ In the present case, a diagnosis of Seckel syndrome was made based on history, delayed development, and clinical features (bird‑headed profile), low set ears, retarded bone age, frontal bossing, hirsutism, dysplastic ears, dilated veins in the temporal region, micropenis, undesended testis. Both the patients also suffered from Glaucoma (Increased pressure in aqueous humour of eye) and hypothyroidism.

The craniofacial features of Seckel syndrome allows its differentiation from other syndromes of growth deficiency with microcephaly, such as Dubowitz syndrome, fetal alcohol syndrome, Trisomy 18 syndrome, DeLange syndrome, and Fanconi syndrome.⁵

The significance of dental alterations in this syndrome resides in the defect, hypoplastic enamel, being limited to the primary dentition, in most instances the second primary molar tooth is not affected.¹⁰ In the present case, both primary and permanent dentition were not hypoplastic.

Children affected with Seckel syndrome do have a normal lifespan although they often have profound mental and physical deficits. Survival of these patients till the age of 75 years has been recorded.⁵ Recurrence of the disease can be suspected by the observation of intrauterine growth retardation with microcephaly in the second trimester of pregnancy, when a first child is born with Seckel syndrome, early molecular antenatal diagnosis can be performed for the couple if the familial mutations have been identified.³