A full-term infant with type II thanatophoric dysplasia

Objectives

To report a neonate with clinical findings consistent with thanatophoric dysplasia (TD). Only a few cases of this rare and lethal skeletal disorder have been reported in South-East Asia.

Case presentation

A 37-year-old Asian female, fourth gravida at 39 weeks, presented to our hospital for an elective cesarean section due to polyhydramnios, frank breech and gestational hypertension. The father was a 42-year-old Asian male. There was no history of rashes, fever, alcohol intake, substance drug abuse, smoking habit or radiation exposure. Ultrasound (US) of 34-weeks’ gestation found a baby with frontal bossing, prominent temporal lobe, clover-skull and low nasal bridge. The thoracic diameter was smaller than the abdominal diameter. Short limbs without bowing were noted in femur and humeral bones. The patient delivered a baby boy, 4115 g, APGAR scores were 5 and 7 at 1 and 5 min. The baby had a dysmorphic face, frontal bossing, low nasal bridge, low-set ears and short neck. The thorax was narrow and abdomen was protuberant. The upper and lower proximal limbs appeared short. A chest X-ray revealed short, curved ribs and opacification of both lungs. He had respiratory distress shortly after birth and had persistent severe respiratory distress despite adequate mechanical ventilation. On the third day, he had cardiac arrest; resuscitation was not done due to family request. The baby was declared deceased due to cardiopulmonary failure related to his congenital anomaly.

Conclusions

Ultrasonography could readily indicate TD prenatally. The pregnancy can continue up to late third trimester without miscarriage. Most of the neonates die in utero; those who survive are dependent on ventilator.

Three-dimensional and four-dimensional HDlive-rendered images of thanatophoric dysplasia

We present herein our first experience with a case of thanatophoric dysplasia (type I) that was diagnosed during the second trimester using three- and four-dimensional HDlive ultrasonography. The HDlive rendering mode clearly showed the anatomical features of thanatophoric dysplasia: external malformations and skeletal abnormalities, including extremely short limbs, flattened vertebral bodies, and short horizontal ribs, among others. HDlive can provide valuable, highly realistic images for the differential diagnosis of skeletal dysplasia. It may also play an important complementary role when conventional two- and three-dimensional ultrasonography does not provide sufficient definition.

Thanatophoric dysplasia: a rare entity

Thanatophoric dysplasia is the lethal skeletal dysplasia characterized by marked underdevelopment of the skeleton and short-limb dwarfism. The child will be having a short neck, narrow thoracic cage and protuberant abdomen. Other anatomical features include a relatively enlarged head with frontal bossing, prominent eyes, hypertelorism and the depressed nasal bridge. The diagnosis is usually made with the ultrasonography in the second trimester. In this study we report a case of this rare entity with emphasis on its anatomical features, abnormalities and clinical profile with relevant review of literature.

Filho RL, Rosa RFM, Maia CR, Graziadio C, Paskulin GA. Diagnóstico pré-natal de displasia tanatofórica: papel do ultrassom fetal

OBJETIVO: Relatar o caso de um paciente com displasia tanatofórica, uma forma autossômica dominante e letal de nanismo, diagnosticado ainda no período pré-natal, e revisar a literatura, discutindo os principais diagnósticos diferenciais e ressaltando a importância do ultrassom fetal na identificação de fetos portadores dessa displasia. DESCRIÇÃO DO CASO: O paciente é o segundo filho de pais jovens sem história familiar de doenças genéticas. O ultrassom fetal realizado com 35 semanas de gestação mostrou polidrâmnio, proeminência frontal e desproporção entre crânio e tronco, com hipoplasia torácica e encurtamento dos ossos longos, compatível com o diagnóstico de displasia tanatofórica. Ao nascimento, a criança era pequena e possuía hipotonia, macrocefalia, fontanelas amplas, hipoplasia de face média, olhos protrusos, hemangioma plano no nariz e pálpebras, nariz em sela, micrognatia, pescoço e tórax curtos e encurtamento importante de braços, antebraços, coxas e pernas. A avaliação radiográfica mostrou crânio com grande diâmetro transverso, tórax com costelas curtas e corpos vertebrais reduzidos, importante encurtamento e deformidade dos ossos longos dos membros superiores e inferiores (os fêmures eram curvos) e hipoplasia da bacia. Esses achados confirmaram o diagnóstico pré-natal de displasia tanatofórica. O paciente evoluiu para o óbito poucos dias após o nascimento devido à insuficiência respiratória. COMENTÁRIOS: A ultrassonografia fetal é um método não invasivo capaz de diagnosticar inúmeras displasias ósseas, incluindo a tanatofórica. A importância do diagnóstico intra-útero reside no fato de que auxilia no diagnóstico diferencial, e permite o aconselhamento genético à família.

Increased nuchal translucency in euploid fetuses--what should we be telling the parents?

Nuchal translucency (NT) measurement between 11 and 14 weeks' gestation is an undisputed marker for aneuploidies. When conventional karyotyping is normal, enlarged NT is a strong marker for adverse pregnancy outcome, associated with miscarriage, intrauterine death, congenital heart defects, and numerous other structural defects and genetic syndromes. The risk of adverse outcome is proportional to the degree of NT enlargement. Although the majority of structural anomalies are amenable to ultrasound detection, unspecified genetic syndromes involving developmental delay may only emerge after birth. Concern over these prenatally undetectable conditions is a heavy burden for parents. However, following detection of enlarged NT the majority of babies with normal detailed ultrasound examination and echocardiography will have an uneventful outcome with no increased risk for developmental delay when compared to the general population. Counseling should emphasize this to help parents restore hope in normal pregnancy outcome and infant development.

Thanatophoric dysplasia type I associated with increased nuchal translucency in the first trimester: Early prenatal diagnosis using combined ultrasonography and molecular biology

A case of thanatophoric dysplasia (TD) type I associated with severely increased nuchal translucency at first trimester screening for Down syndrome is reported. A 38-year-old woman, G2P1, with previous uneventful pregnancy, was referred for amniocentesis at 16 weeks due to positive first trimester integrated test. Amniocentesis revealed a 46,XX fetus. At 16 weeks gestation, the ultrasound examination of the fetus revealed a narrow chest, short ribs, and a generalized severe shortening of the long bones. The patient underwent a follow-up scan at 19 weeks which demonstrated ultrasound findings consistent with severe rhizomelic micromelia. A wide prenatal panel of gene mutations related with skeletal dysplasia was performed. Nucleotidic sequence using QF-PCR on exons 7,10, 15, 19 of the fibroblast growth factor receptor 3 (FGFR3) demonstrated a 742 C>T (R248C) mutation, which resulted in an Arg248Cys substitution in heterozygous state, leading to a prenatal diagnosis of thanatophoric dysplasia type I. The early diagnosis of this lethal form of skeletal dysplasia directed the prenatal counseling and allowed appropriate obstetric management. Necropsy, post-mortem x-ray, and histologic analysis of the growth plate might aid the diagnosis of TD type I.