Diagnosis of Joubert syndrome via ultrasonography

Joubert Syndrome: A Molar Tooth Sign in Disguise

Joubert syndrome (JS) is a rare genetic ciliopathy characterized by the aplasia or malformation of the midbrain and or hindbrain structures. It usually manifests during the early stages with nonspecific neurological symptoms that progress to involve multiple systems. Its presentation similarity to other neurological disorders makes the diagnosis difficult, hence causing a delay in treatment and worse prognosis due to complications. If undiagnosed during childhood, it often presents during adolescence with the most common complication of acute kidney injury due to nephronophthisis. Here, we present a case of JS in late adolescence with renal complications and other neurological abnormalities. We aim to emphasize the importance of its early diagnosis by physicians in childhood to prevent further complications. It also highlights the possible diagnostic value and significance of brain imaging in the early stages when only mild mental retardation signs may be the only clues.

Prenatal diagnosis of Joubert syndrome: A case report and literature review

INTRODUCTION

Joubert syndrome (JS) is a rare autosomal recessive inherited disease belonging to ciliopathy with the causative mutation of genes. Except for X-linked inheritance, the high recurrence rate of a family is about 25%. After birth, it may cause a series of neurological symptoms, even with retina, kidney, liver, and other organ abnormalities, which is defined as Joubert syndrome and related disorders (JSRD). Molecular genetics research contributes to disease prediction and genetic counseling. Prenatal diagnosis is rare. Magnetic resonance imaging (MRI) is usually the first-choice diagnostic modality with typical brain images characterized by the molar tooth sign. We describe a case of JS prenatally and Dandy-Walker malformation for the differential diagnosis based on ultrasonograms. We also review the etiology, imaging features, clinical symptoms, and diagnosis of JSRD.

CASE PRESENTATION

A 22-year-old woman was pregnant at 27 1/7 weeks' gestation with fetal cerebellar vermis hypoplasia. Fetal ultrasonography and MRI confirmed a diagnosis of JS at our center. The couple finally opted to terminate the fetus, which had a normal appearance and growth parameters. The couple also had an AHI1 gene mutation on chromosome 6.

CONCLUSIONS

Currently, a diagnosis of JS is commonly made after birth. Fewer cases of prenatal diagnosis by ultrasonography have been made, and they are more liable to be misdirected because of some nonspecial features that also manifest in Dandy-Walker malformation, cranio-cerebello-cardiac syndrome, and so on.